IL274292A

Chimeric antigen receptors specific for b-cell maturation antigen and encoding polynucleotides

Abstract

This record has no abstract on file.

Term

No projected expiry on record.

  1. Priority
  2. Filed
  3. Published
  4. Today

3 claims: 1 independent, 2 dependent

  1. 1
    CLAIMS WHAT IS CLAIMED:1. A chimeric antigen receptor comprising: (a) an extracellular antigen-binding domain that specifically recognizes B cell maturation antigen (BCMA);(b) a spacer of at least 125 amino acids in length;(c) a transmembrane domain;and (d) an intracellular signaling region. 2. The chimeric antigen receptor of claim 1, wherein the spacer comprises a portion of an immunoglobulin constant region. 3. The chimeric antigen receptor of claim 1 or claim 2, wherein the spacer comprises a sequence of a hinge region, a Ch2 region and a Ch3 region. 4. The chimeric antigen receptor of claim 3, wherein the hinge region comprises all or a portion of an IgG4 hinge region and/or of an IgG2 hinge region, wherein the IgG4 hinge region is optionally a human IgG4 hinge region and the IgG2 hinge region is optionally a human IgG2 hinge region;the CH2 region comprises all or a portion of an IgG4 CH2 region and/or of an IgG2 CH2 region, wherein the IgG4 CH2 region is optionally a human IgG4 CH2 region and the IgG2 CH2 region is optionally a human IgG2 CH2 region;and/or the CH3 region comprises all or a portion of an IgG4 CH3 region and/or of an IgG2 CH3 region, wherein the IgG4 CH3 region is optionally a human IgG4 CH3 region and the IgG2 CH3 region is optionally a human IgG2 CH3 region. 5. The chimeric antigen receptor of claim 3or claim 4, wherein the hinge, Ch2 and Ch3 comprises all or a portion of each of a hinge region, Ch2 and Ch3 from IgG4. 6. The chimeric antigen receptor of claim 3 or claim 4, wherein: the hinge region is chimeric and comprises a hinge region from human IgG4 and human IgG2;363 the Ch2 region is chimeric and comprises a Ch2 region from human IgG4 and human IgG2;and/or the Ch3 region is chimeric and comprises a Ch3 region from human IgG4 and human IgG2. 7. The chimeric antigen receptor of claim any of claims 1-6, wherein the spacer comprises an IgG4/2 chimeric hinge or a modified IgG4 hinge comprising at least one amino acid replacement compared to human IgG4 hinge region;an human IgG2/4 chimeric Ch2 region;and a human IgG4 Ch3 region. 8. The chimeric antigen receptor of any of claims 1-4, 6 and 7, wherein the spacer is or comprises (i) the sequence set forth in SEQ ID NO: 649;(ii) a functional variant of SEQ ID NO:649 that has at least 95%, 96%, 97%, 98% or 99% sequence identity to SEQ ID NO:649;or (iii) a contiguous portion of (i) or (ii) that is at least 125 amino acids in length. 9. The chimeric antigen receptor of any of claims 1-3 and 6-8, wherein the spacer is or comprises the sequence set forth in SEQ ID NO: 649. 10. A chimeric antigen receptor comprising: (a) an extracellular antigen-binding domain that specifically recognizes B cell maturation antigen (BCMA);(b) a spacer set forth in SEQ ID NO:649;(c) a transmembrane domain;and (d) an intracellular signaling region. 11. The chimeric antigen receptor of any of claims 1-10, wherein the antigen-binding domain is an antibody fragment comprising a variable heavy chain (Vh) and a variable light chain (VL) region. 12. The chimeric antigen receptor of claim 11, wherein: the Vh region is or comprises an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the VH region amino acid sequence set forth in any of SEQ ID NOs: 617, 115, 256, 519, or 609;and 364 the VLregion is or comprises an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the VLregion amino acid sequence set forth in any of SEQ ID NOs: 618, 267, 535, 536, or 610. 13. The chimeric antigen receptor of claim 11 or claim 12, wherein: the VH region and the VL regions comprise the amino acid sequence set forth in SEQ ID NOs:617 and 618, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:617 and 618, respectively;the VH region and the VL regions comprise the amino acid sequence set forth in SEQ ID NOs:256 and 267, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:256 and 267, respectively;the Vh region and the Vl regions comprise the amino acid sequence set forth in SEQ ID NOs:519 and 535, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:519 and 535, respectively;the Vh region and the Vl regions comprise the amino acid sequence set forth in SEQ ID NOs: 115 and 536, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS: 115 and 536, respectively;or the VH region and the VL regions comprise the amino acid sequence set forth in SEQ ID NOs:609 and 610, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:609 and 610, respectively. 14. The chimeric antigen receptor of any of claims 11-13, wherein the VH region and the Ytregions comprise the amino acid sequence set forth in SEQ ID NOs:617 and 618, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:617 and 618, respectively. 15. The chimeric antigen receptor of any of claims 11-13, wherein: the Vh region comprises a heavy chain complementarity determining region 1 (CDRHl), a heavy chain complementarity determining region 2 (CDR-H2) and a heavy chain complementarity determining region 3 (CDR-H3) contained within the VH region amino acid sequence selected from any one of SEQ ID NOs: 617, 115, 256, 519, or 609;and 365 the VLregion comprises a light chain complementarity determining region 1 (CDR-L1), a light chain complementarity determining region 2 (CDR-L2) and a light chain complementarity determining region 3 (CDR-L3) contained within the Vl region amino acid sequence selected from any one of SEQ ID NOs: 618, 267, 535, 536, or 610. 16. The chimeric antigen receptor of any of claims 11-15, wherein: the Vh region comprises a CDR-H1, CDR-H2 and CDR-H3 contained within the Vh region amino acid sequence set forth in SEQ ID NO: 617;and the VLregion comprises a CDRLI, CDR-L2 and CDR-L3 contained within the VLregion amino acid sequence set forth in SEQ ID NO: 618. 17. The chimeric antigen receptor of any of claims 11-13 and 15, wherein: the VH region comprises (a) a CDR-H1 comprising the amino acid sequence selected from any one of SEQ ID NOs:l, 2, 507 or 593;(b) a CDR-H2 comprising the amino acid sequence selected from any one of SEQ ID NOs: 4, 5, 513 or 594;and (c) a CDR-H3 comprising the amino acid sequence selected from any one of SEQ ID NOs:7, 10, 157, 517 or 595;and the VL region comprises (a) a CDR-L1 comprising the amino acid sequence selected from any one of SEQ ID NOs:33, 178, 380, 589 or 601;(b) a CDR-L2 comprising the amino acid sequence selected from any one of SEQ ID NOs: 43, 183, 400, 590 or 602;and (c) a CDRL3 comprising the amino acid sequence selected from any one of SEQ ID NOs: 194, 416, 421, 591 or 603. 18. The chimeric antigen receptor of any of claims 11-13, 15 and 17, wherein: the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:593, 594, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:2, 5, and 157, respectively, and the VLregion comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS: 178, 183, and 194, respectively;366 the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:1, 4, and 7, respectively, and the VLregion comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:380, 400, and 416, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:2, 5, and 10, respectively, and the VLregion comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:33, 43, and 421, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:507, 513, and 517, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:589, 590, and 591, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:596, 597, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:598, 599, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;or the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:611, 612, and 613, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:614, 615, and 603, respectively. 19. The chimeric antigen receptor of any of claims 11-18, wherein the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:593, 594, and 595, respectively, and the VLregion comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively. 20. The chimeric antigen receptor of any of claims 11-13, 15, 17 and 18, wherein the Vh region is or comprises the amino acid sequence set forth in any of SEQ ID NOs: 617, 115, 367 256, 519, or 609;and the VLregion is or comprises the amino acid sequence set forth in any of SEQ ID NOs: 618, 267, 535, 536, or 610. 21. The chimeric antigen receptor of any of claims 11-13, 15, 17, 18 and 20, wherein: the VH region is or comprises the amino acid sequence set forth in SEQ ID NO: 617;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:618 the Vh region is or comprises the amino acid sequence set forth in SEQ ID NO: 256;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:267;the VH region is or comprises the amino acid sequence set forth in SEQ ID NO: 519;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:535;the Vh region is or comprises the amino acid sequence set forth in SEQ ID NO: 115;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:536;or the VH region is or comprises the amino acid sequence set forth in SEQ ID NO: 609;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:610. 22. The chimeric antigen receptor of any of claims 11-21, wherein: the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOs:593, 594, and 595, respectively;or the VH region comprises a CDRHl, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOs:611, 612, and 613, respectively;and the VL region comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOs:601, 602, and 603, respectively;or the VL region comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOs:614, 615, and 603, respectively. 23. The chimeric antigen receptor of any of claims 11-22, wherein the VH region is or comprises the amino acid sequence set forth in SEQ ID NO: 617;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO: 618. 24. The chimeric antigen receptor of any of claims 11-23, wherein the fragment comprises an scFv. 368 25. The chimeric antigen receptor of any of claims 11-24, when the VH region and the VL region are joined by a flexible linker. 26. The chimeric antigen receptor of claim 25, wherein the scFv comprises a linker comprising the amino acid sequence GGGGSGGGGSGGGGS (SEQ ID NO:361). 27. The chimeric antigen receptor of any of claims 11-26, wherein the Vh region is amino-terminal to the Vl region. 28. The chimeric antigen receptor of any of claims 11-27, wherein the antigenbinding domain comprises the amino acid sequence selected from any one of SEQ ID NOs: 478, 128-139, 268-278, 329, 442, 558-576, 578-583, 585, or 769-771 or an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the amino acid sequence selected from any one of SEQ ID NOs: 478, 128-139, 268-278, 329, 442, 558-576, 578-583, 585, or 769-771. 29. The chimeric antigen receptor of any of claims 1-28, wherein the antigen-binding domain comprises the amino acid sequence selected from any one of SEQ ID NOs: 478, 278, 559, 560, or 442 or an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the amino acid sequence selected from any one of SEQ ID NOs: 478, 278, 559, 560, or 442. 30. The chimeric antigen receptor of any of claims 1-29, wherein the antigen-binding domain comprises the amino acid sequence set forth in SEQ ID NO: 478 or an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 478. 31. The chimeric antigen receptor of any of claims 1-30, wherein the antigen-binding domain comprises the amino acid sequence set forth in SEQ ID NO: 478. 32. The chimeric antigen receptor of any of claims 1-31, wherein a nucleic acid encoding the antigen-binding domain comprises (a) the sequence of nucleotides set forth in any 369 of SEQ ID NOS: 648, 352, 647, 716, or 718;(b) a sequence of nucleotides that has at least 90% sequence identity to any of SEQ ID NOS: 648, 352, 647, 716, or 718;or (c) a degenerate sequence of (a) or (b). 33. The chimeric antigen receptor of any of claims 1-32, wherein the nucleic acid encoding the antigen-binding domain comprises the sequence of nucleotides set forth in any of SEQ ID NO: 460, 440, 715, 717 or 719. 34. The chimeric antigen receptor of any of claims 1-33, wherein the nucleic acid encoding the antigen-binding domain comprises the sequence of nucleotides set forth in SEQ ID NO:460. 35. The chimeric antigen receptor of any of claims 11-26, wherein the VH region is carboxy-terminal to the VL region. 36. A chimeric antigen receptor, comprising: (1) an extracellular antigen-binding domain that specifically binds human B cell maturation antigen (BCMA), wherein the extracellular antigen-binding domain comprises: (i) a variable heavy chain (Vh) comprising an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the Vh region amino acid sequence set forth in SEQ ID NO: 617;and (ii) a variable light chain (VL) region comprising an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the Vl region amino acid sequence set forth in any of SEQ ID NO: 618;
  2. 2
    (2) a spacer comprising an IgG4/2 chimeric hinge or a modified IgG4 hinge; an IgG2/4 chimeric Ch2 region; and an IgG4 Ch3 region, optionally that is about 228 amino acids in length; or a spacer set forth in SEQ ID NO:649;
  3. 3
    (3) a transmembrane domain, optionally a transmembrane domain from a human CD28; and (4) an intracellular signaling region comprising a cytoplasmic signaling domain of a CD3-zeta (Οϋ3ζ) chain and an intracellular signaling domain of a T cell costimulatory molecule. 370 37. The chimeric antigen receptor of claim 36, wherein:the Vh region comprises a CDR-H1, CDR-H2 and CDR-H3 contained within the Vh region amino acid sequence set forth in SEQ ID NO: 617;and the Vl region comprises a CDRLI, CDR-L2 and CDR-L3 contained within the VL region amino acid sequence set forth in SEQ ID NO: 618;the Vh region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:593, 594, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;the Vh region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:596, 597, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;the Vh region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:598, 599, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;or the Vh region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:611, 612, and 613, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:614, 615, and 603, respectively. 38. A chimeric antigen receptor, comprising: (1) an extracellular antigen-binding domain that specifically binds human B cell maturation antigen (BCMA), wherein the extracellular antigen-binding domain comprises: a variable heavy (Vh) region comprising a CDR-H1, CDR-H2 and CDR-H3 contained within the Vh region amino acid sequence set forth in SEQ ID NO: 617;and a variable light (VL) region comprising a CDR-L1, CDR-L2 and CDR-L3 contained within the VL region amino acid sequence set forth in SEQ ID NO: 618;or a Vh region comprising a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:593, 594, and 595, respectively, and a Vl region comprising a CDR 371 LI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;a Vh region comprising a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:596, 597, and 595, respectively, and a Vl region comprising a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;a Vh region comprising a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:598, 599, and 595, respectively, and a Vl region comprising a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;or a Vh region comprising a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:611, 612, and 613, respectively, and a Vl region comprising a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:614, 615, and 603, respectively;(2) a spacer comprising an IgG4/2 chimeric hinge or a modified IgG4 hinge;an IgG2/4 chimeric Ch2 region;and an IgG4 Ch3 region, optionally that is about 228 amino acids in length;or a spacer set forth in SEQ ID NO: 649;(3) a transmembrane domain, optionally a transmembrane domain from a human CD28;and (4) an intracellular signaling region comprising a cytoplasmic signaling domain of a CD3-zeta (Οϋ3ζ) chain and an intracellular signaling domain of a T cell costimulatory molecule. 39. The chimeric antigen receptor of any of claims 36-38, wherein the extracellular antigen-binding domain comprises the VH region amino acid sequence set forth in SEQ ID NO:617 and the VL region amino acid sequence set forth in SEQ ID NO:618. 40. The chimeric antigen receptor of any of claims 1-35, wherein the intracellular signaling region comprises an activating cytoplasmic signaling domain. 41. The chimeric antigen receptor of claim 40, wherein the activating cytoplasmic signaling domain is capable of inducing a primary activation signal in a T cell, is a T cell 372 receptor (TCR) component and/or comprises an immunoreceptor tyrosine-based activation motif (ITAM). 42. The chimeric antigen receptor of claim 40 or claim 41, wherein the activating cytoplasmic signaling domain is or comprises a cytoplasmic signaling domain of a CD3-zeta (Εϋ3ζ) chain or a functional variant or signaling portion thereof. 43. The chimeric antigen receptor of any of claims 40-42, wherein the activating cytoplasmic domain is human or is from a human protein. 44. The chimeric antigen receptor of any of claims 36-39, 42 and 43, wherein thecytoplasmic signaling domain is or comprises the sequence set forth in SEQ ID NO:628 or a sequence of amino acids that has at least 90% sequence identity to SEQ ID NO:628. 45. The chimeric antigen receptor of any of claims 40-44, wherein the intracellular signaling region further comprises a costimulatory signaling region. 46. The chimeric antigen receptor of claim 45, wherein the costimulatory signaling region comprises an intracellular signaling domain of a T cell costimulatory molecule or a signaling portion thereof. 47. The chimeric antigen receptor of any of claims 36-39, 45 and 46, wherein the costimulatory signaling region comprises an intracellular signaling domain of a CD28, a 4-1BB or an ICOS or a signaling portion thereof. 48. The chimeric antigen receptor of any of claims 36-39 and 45-47, wherein the costimulatory signaling region comprises an intracellular signaling domain of 4-IBB. 49. The chimeric antigen receptor of any of claims 36-39 and 45-48, wherein the costimulatory signaling region is human or is from a human protein. 373 50. The chimeric antigen receptor of any of claims 36-39 and 45-49, wherein the costimulatory signaling region is or comprises the sequence set forth in SEQ ID NO:626 or a sequence of amino acids that exhibits at least 90% sequence identity to the sequence set forth in SEQ ID NO: 626. 51. The chimeric antigen receptor of any of claims 36-50, wherein the costimulatory signaling region is between the transmembrane domain and the intracellular signaling region. 52. The chimeric antigen receptor of any of claims 1-51, wherein the transmembrane domain is or comprises a transmembrane domain from CD4, CD28, or CD8. 53. The chimeric antigen receptor of claim 52, wherein the transmembrane domain is or comprises a transmembrane domain from a CD28. 54. The chimeric antigen receptor of any of claims 1-53, wherein the transmembrane domain is human or is from a human protein. 55. The chimeric antigen receptor of any of claims 1-54, wherein the transmembrane domain is or comprises the sequence set forth in SEQ ID NO:624 or a sequence of amino acids that exhibits at least 90% sequence identity to SEQ ID NO:624. 56. The chimeric antigen receptor of any of claims 1-55, wherein the chimeric antigen receptor comprises from its N to C terminus in order: the antigen-binding domain, the spacer, the transmembrane domain and the intracellular signaling domain. 57. The chimeric antigen receptor of any of claims 1-56, wherein (a) the ability ofthe antigen binding domain or of the chimeric antigen receptor to bind to BCMA expressed on the surface of a target cell, or (b) a measure indicative of function or activity of the chimeric antigen receptor following exposure of cells expressing the chimeric antigen receptor to cells expressing surface BCMA, is not reduced or blocked or is not substantially reduced or blocked in the presence of a concentration or amount of a soluble or shed form of BCMA, wherein the concentration or amount is a concentration or amount capable of blocking or reducing or 374 substantially blocking or reducing binding or a measure of function or activity associated with a reference anti-BCMA recombinant receptor or a reference anti-BCMA binding domain, under the same or substantially the same conditions, or is a concentration or amount present in a biological sample. 58. The chimeric antigen receptor of claim 57, wherein the concentration or amount of the soluble or shed form of the BCMA: is a concentration or amount present in serum or blood or plasma of the subject or of a multiple myeloma patient, or an average concentration or amount present in serum, blood or plasma of patients within a patient population having multiple myeloma or a subtype or subpopulation thereof, or is a concentration or amount at which the binding or measure is reduced or blocked, or is substantially reduced or blocked, for a reference anti-BCMA recombinant receptor, optionally a reference anti-BCMA CAR, under the same or substantially the same conditions. 59. The chimeric antigen receptor of any of claims 1-58, wherein the chimeric antigen receptor is encoded by a polynucleotide sequence comprising the sequence set forth in any of SEQ ID NOS: 751-756 or by a sequence that exhibits at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the sequence set forth in any of SEQ ID NOS: 751-756. 60. The chimeric antigen receptor of any of claims 1-59, wherein the chimeric antigen receptor is encoded by a polynucleotide sequence comprising the sequence set forth in any of SEQ ID NOS: 755 and 756 or by a sequence that exhibits at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the sequence set forth in any of SEQ ID NOS: 755 and 756. 61. The chimeric antigen receptor of any of claims 1-60, wherein the chimeric antigen receptor is encoded by a polynucleotide sequence comprising the sequence set forth in SEQ ID NO: 755 or by a sequence that exhibits at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity thereto. 375 62. The chimeric antigen receptor of any of claims 1-61, wherein the chimeric antigen receptor is encoded by a polynucleotide sequence comprising the sequence set forth in SEQ ID NO: 755. 63. A polynucleotide encoding the chimeric antigen receptor of any of claims 1-62. 64. The polynucleotide of claim 63, wherein following expression of the polynucleotide in a human cell, optionally a human T cell, the RNA, optionally the messenger RNA (mRNA), from the polynucleotide, exhibits at least 70%, 75%, 80%, 85%, 90%, or 95% RNA homogeneity. 65. The polynucleotide of claim 63 or claim 64, wherein the encoded chimeric antigen receptor comprises a spacer comprising an IgG4/2 chimeric hinge or a modified IgG4 hinge;an IgG2/4 chimeric Ch2 region;and an IgG4 Ch3 region, optionally that is about 228 amino acids in length;or a spacer set forth in SEQ ID NO: 649 a functional variant of SEQ ID NO:649 that has at least 95%, 96%, 97%, 98% or 99% sequence identity to SEQ ID NO:649. 66. A polynucleotide encoding a chimeric antigen receptor, comprising nucleic acid encoding: (a) an extracellular antigen-binding domain that specifically recognizes an antigen;(b) a spacer of at least 125 amino acids in length;(c) a transmembrane domain;and (d) an intracellular signaling region, wherein following expression of the polynucleotide in a human cell, optionally a human T cell, the transcribed RNA, optionally messenger RNA (mRNA), from the polynucleotide, exhibits at least 70%, 75%, 80%, 85%, 90%, or 95% RNA homogeneity. 67. The polynucleotide of any of claims 63-66, wherein the encoded spacer comprises a portion of an immunoglobulin. 68. The polynucleotide of any of claims 63-67, wherein the encoded spacer comprises a sequence of a hinge region, a Ch2 region and a Ch3 region. 69. The polynucleotide of any of claims 63, 64 and 66-68, wherein 376 the hinge region comprises all or a portion of an IgG4 hinge region and/or of an IgG2 hinge region, wherein the IgG4 hinge region is optionally a human IgG4 hinge region and the IgG2 hinge region is optionally a human IgG2 hinge region;the CH2 region comprises all or a portion of an IgG4 CH2 region and/or of an IgG2 CH2 region, wherein the IgG4 CH2 region is optionally a human IgG4 CH2 region and the IgG2 CH2 region is optionally a human IgG2 CH2 region;and/or the CH3 region comprises all or a portion of an IgG4 CH3 region and/or of an IgG2 CH3 region, wherein the IgG4 CH3 region is optionally a human IgG4 CH3 region and the IgG2 CH3 region is optionally a human IgG2 CH3 region. 70. The polynucleotide of any of claims 63, 64 and 66-69, wherein the hinge, Ch2 and Ch3 comprises all or a portion of each of a hinge region, Ch2 and Ch3 from IgG4. 71. The polynucleotide of any of claims 63, 64 and 66-69, wherein: the hinge region is chimeric and comprises a hinge region from human IgG4 and human IgG2;the Ch2 region is chimeric and comprises a Ch2 region from human IgG4 and human IgG2;and/or the Ch3 region is chimeric and comprises a Ch3 region from human IgG4 and human IgG2 72. The polynucleotide of claim any of claims 63, 64 and 66-71, wherein the spacer comprises an IgG4/2 chimeric hinge or a modified IgG4 hinge comprising at least one amino acid replacement compared to human IgG4 hinge region;an human IgG2/4 chimeric Ch2 region;and a human IgG4 Ch3 region. 73. The polynucleotide of any of claims 63, 64 and 66-72, wherein the encoded spacer is or comprises (i) the sequence set forth in SEQ ID NO: 649;(ii) a functional variant of SEQ ID NO:649 that has at least 95%, 96%, 97%, 98% or 99% sequence identity to SEQ ID NO:649;or (iii) a contiguous portion of (i) or (ii) that is at least 125 amino acids in length. 377 74. The polynucleotide of any of claims 63-73, wherein the encoded spacer is or comprises the sequence set forth in SEQ ID NO: 649. 75. The polynucleotide of any of claims 63-74, wherein the nucleic acid encoding the spacer comprises at least one modified splice donor and/or splice acceptor site, said modified splice donor and/or acceptor site comprising one or more nucleotide modifications corresponding to a reference splice donor site and/or reference splice acceptor site contained in the sequence set forth in SEQ ID NO:621. 76. The polynucleotide of claim 75, wherein the one or more nucleotide modifications comprise a nucleotide substitution. 77. The polynucleotide of claim 75 or claim 76, wherein the reference splice donor and/or reference splice acceptor sites are canonical, non-canonical, or cryptic splice sites. 78. The polynucleotide of any of claim 75-77, wherein: the reference splice donor and/or reference splice acceptor site(s) has a splice site prediction score of at least or about 0.4, 0.5, 0.6, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 0.99, or 1.0;and/or the reference splice donor and/or reference splice acceptor site(s) is/are predicted to be involved in a splice event with a probability of at least 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100%. 79. The polynucleotide of any of claims 75-78, wherein: the reference splice donor site comprises the sequence aatctaagtacggac (SEQ ID NO: 705), tcaactggtacgtgg (SEQ ID NO:706), acaattagtaaggca (SEQ ID NO:707) and/or accacaggtgtatac (SEQ ID NO:708);and/or the reference splice acceptor site comprises the sequence aagtttctttctgtattccaggctgaccgtggataaatctc (SEQ ID NO:742) and/or gggcaacgtgttctcttgcagtgtcatgcacgaagccctgc (SEQ ID NO:743). 80. The polynucleotide of any of claims 75-78, wherein: 378 the reference splice donor and/or reference splice acceptor site(s) has a splice site prediction score of at least or about 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 0.99, or 1.0;and/or the reference splice donor and/or reference splice acceptor site(s) is/are predicted to be involved in a splice event with a probability of at least 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100%. 81. The polynucleotide of any of claims 75-78 and 80, wherein: the reference splice donor site comprises the sequence tcaactggtacgtgg (SEQ ID NO:706);and/or the reference splice acceptor site comprises the sequence aagtttctttctgtattccaggctgaccgtggataaatctc (SEQ ID NO:742). 82. The polynucleotide of any of claims 75-81, wherein at least one of the one or more nucleotide modifications are within 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 residues of the splice site junction of the reference splice acceptor and/or reference splice donor site. 83. The polynucleotide of any of claims 75-82, wherein the one or more nucleotide modifications is silent and/or results in a degenerate codon compared to SEQ ID NO:621 and/or does not change the amino acid sequence of the encoded spacer. 84. The polynucleotide of any of claims 75-83, wherein: the modified splice donor site is set forth in agtctaaatacggac (SEQ ID NO:661), tcaactggtatgtgg (SEQ ID NO:662), accatctccaaggcc (SEQ ID NO:663) and/or gccccaggtttacac (SEQ ID NO:664);and/or the modified splice acceptor site is set forth in cagtttcttcctgtatagtagactcaccgtggataaatcaa (SEQ ID NO:672), gggcaacgtgttcagctgcagcgtgatgcacgaggccctgc (SEQ ID NO: 673) and/or cgccttgtcctccttgtcccgctcctcctgttgccggacct (SEQ ID NO:766). 85. The polynucleotide of any of claims 75-84, wherein the modified splice donor site is set forth in tcaactggtatgtgg (SEQ ID NO:662) and/or the modified acceptor site is set forth in cagtttcttcctgtatagtagactcaccgtggataaatcaa (SEQ ID NO:672) and/or cgccttgtcctccttgtcccgctcctcctgttgccggacct (SEQ ID NO:766). 379 86. The polynucleotide of any of claims 63-85, wherein the spacer is encoded bythe nucleotide sequence set forth in SEQ ID NO:622 or a portion thereof. 87. A polynucleotide encoding a chimeric antigen receptor, wherein the polynucleotide comprises nucleic acid encoding: (a) an extracellular antigen-binding domain that specifically recognizes an antigen;(b) a spacer, wherein the encoding nucleic acid is or comprises the sequence set forth in SEQ ID NO:622 or encodes a sequence of amino acids set forth in SEQ ID NO:649;(c) a transmembrane domain;and (d) an intracellular signaling region. 88. A polynucleotide encoding a chimeric antigen receptor, wherein the polynucleotide comprises nucleic acid encoding: (a) an extracellular antigen-binding domain that specifically recognizes an antigen;(b) a spacer, wherein the encoding nucleic acid consists or consists essentially of the sequence set forth in SEQ ID NO:622 or encodes a sequence of amino acids set forth in SEQ ID NO:649;(c) a transmembrane domain;and (d) an intracellular signaling region. 89. The polynucleotide of claim 87 or claim 88, wherein following expression of the polynucleotide in a cell, the transcribed RNA, optionally messenger RNA (mRNA), from the polynucleotide, exhibits at least 70%, 75%, 80%, 85%, 90%, or 95% RNA homogeneity. 90. The polynucleotide of any of claims 63-89, wherein, following expression in a human cell, optionally a human T cell, the transcribed RNA, optionally messenger RNA (mRNA), from the polynucleotide exhibits reduced heterogeneity compared to the heterogeneity of the mRNA transcribed from a reference polynucleotide, said reference polynucleotide encoding the same amino acid sequence as the polynucleotide, wherein the reference polynucleotide differs by the presence of one or more splice donor site and/or one or more splice acceptor site in the nucleic acid encoding the spacer and/or comprises one or more nucleotide modifications compared to the polynucleotide and/or comprises the sequence set forth in SEQ IDNO:621. 380 91. The polynucleotide of claim 90, wherein the RNA heterogeneity is reduced by greater than or greater than about 10%, 15%, 20%, 25%, 30%, 40%, 50% or more. 92. The polynucleotide of claim 90 or claim 91, wherein the transcribed RNA, optionally messenger RNA (mRNA), from the reference polynucleotide exhibits greater than or greater than about 10%, 15%, 20%, 25%, 30%, 40%, 50% or more RNA heterogeneity. 93. The polynucleotide of any of claims 63-92, wherein the RNA homogeneity and/or heterogeneity is determined by agarose gel electrophoresis, chip-based capillary electrophoresis, analytical ultracentrifugation, field flow fractionation, or liquid chromatography. 94. The polynucleotide of any of claims 63-93, wherein the polynucleotide is codonoptimized for expression in a human cell. 95. The polynucleotide of any of claims 63-94, wherein the antigen is associated with a disease or condition or is expressed in cells of the environment of a lesion associated with the disease or condition. 96. The polynucleotide of any of claims 63-95, wherein the disease or condition is a cancer. 97. The polynucleotide of any of claims 63-96, wherein the disease or condition is a myeloma, leukemia or lymphoma. 98. The polynucleotide of any of claims 63-97, wherein the antigen is B cell maturation antigen (BCMA), ROR1, carbonic anhydrase 9 (CAIX), tEGFR, Her2/neu (receptor tyrosine kinase erbB2), Ll-CAM, CD19, CD20, CD22, mesothelin, CEA, and hepatitis B surface antigen, anti-folate receptor, CD23, CD24, CD30, CD33, CD38, CD44, EGFR, epithelial glycoprotein 2 (EPG-9), epithelial glycoprotein 40 (EPG-40), EPHa2, erb-B2, erb-B3, erb-B4, erbB dimers, EGFR vIII, folate binding protein (FBP), FCRL5, FCRH5, fetal acetylcholine receptor, GD2, GD3, G protein-coupled receptor class C group 5 member D 381 (GPRC5D), HMW-MAA, IL-92R-alpha, IL-13R-alpha2, kinase insert domain receptor (kdr), kappa light chain, Lewis Y, Ll-cell adhesion molecule, (Ll-CAM), Melanoma-associated antigen (MAGE)-Al, MAGE-A3, MAGE-A6, Preferentially expressed antigen of melanoma (PRAME), survivin, TAG72, B7-H6, IL-13 receptor alpha 2 (IL-13Ra2), CA9, GD3, HMWMAA, CD171, G250/CAIX, HLA-AI MAGE Al, HLA-A2 NY-ESO-1, PSCA, folate receptor-a, CD44v6, CD44v7/8, avb6 integrin, 8H9, NCAM, VEGF receptors, 5T4, Foetal AchR, NKG2D ligands, CD44v6, dual antigen, a cancer-testes antigen, mesothelin, murine CMV, mucin 1 (MUC1), MUC16, PSCA, NKG2D, NY-ESO-1, MART-1, gplOO, oncofetal antigen, ROR1, TAG72, VEGF-R2, carcinoembryonic antigen (CEA), Her2/neu, estrogen receptor, progesterone receptor, ephrinB2, CD123, c-Met, GD-9, O-acetylated GD2 (OGD2), CE7, Wilms Tumor 1 (WT-1), a cyclin, cyclin A2, CCL-1, CD138, a pathogen-specific antigen. 99. The polynucleotide of claim 98, wherein the antigen is B cell maturation antigen (BCMA). 100. The polynucleotide of any of claims 63-99, wherein the encoded antigen-binding domain is an antibody fragment comprising a variable heavy chain (VH) and a variable light chain (VL) region. 101. The polynucleotide of claim 100, wherein: the VH region is or comprises an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the VH region amino acid sequence set forth in any of SEQ ID NOs: 617, 115, 256, 519, or 609;and the VLregion is or comprises an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the VLregion amino acid sequence set forth in any of SEQ ID NOs: 618, 267, 535, 536, or 610. 102. The polynucleotide of claim 100 or claim 101, wherein: the VH region and the VL regions comprise the amino acid sequence set forth in SEQ ID NOs:617 and 618, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:617 and 618, respectively;382 the VH region and the VL regions comprise the amino acid sequence set forth in SEQ ID NOs:256 and 267, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:256 and 267, respectively;the Vh region and the Vl regions comprise the amino acid sequence set forth in SEQ ID NOs:519 and 535, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:519 and 535, respectively;the Vh region and the Vl regions comprise the amino acid sequence set forth in SEQ ID NOs:115 and 536, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS: 115 and 536, respectively;or the VH region and the VL regions comprise the amino acid sequence set forth in SEQ ID NOs:609 and 610, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:609 and 610, respectively. 103. The polynucleotide of any of claims 100-102, wherein the VH region and the VL regions comprise the amino acid sequence set forth in SEQ ID NOs:617 and 618, respectively, or a sequence of amino acids having at least 90% identity to SEQ ID NOS:617 and 618, respectively. 104. The polynucleotide of any of claims 100-102, wherein: the Vh region comprises a heavy chain complementarity determining region 1 (CDRHl), a heavy chain complementarity determining region 2 (CDR-H2) and a heavy chain complementarity determining region 3 (CDR-H3) contained within the VH region amino acid sequence selected from any one of SEQ ID NOs: 617, 115, 256, 519, or 609;and the Vlregion comprises a light chain complementarity determining region 1 (CDR-L1), a light chain complementarity determining region 2 (CDR-L2) and a light chain complementarity determining region 3 (CDR-L3) contained within the VL region amino acid sequence selected from any one of SEQ ID NOs: 618, 267, 535, 536, or 610. 105. The polynucleotide of any of claims 100-104, wherein: the Vh region comprises a CDR-H1, CDR-H2 and CDR-H3 contained within the Vh region amino acid sequence set forth in SEQ ID NO: 617;and the VLregion comprises a CDR383 LI, CDR-L2 and CDR-L3 contained within the VLregion amino acid sequence set forth in SEQ ID NO: 618. 106. The polynucleotide of any of claims 100-102 and 104, wherein: the VH region comprises (a) a CDR-H1 comprising the amino acid sequence selected from any one of SEQ ID NOs:l, 2, 507 or 593;(b) a CDR-H2 comprising the amino acid sequence selected from any one of SEQ ID NOs: 4, 5, 513 or 594;and (c) a CDR-H3 comprising the amino acid sequence selected from any one of SEQ ID NOs:7, 10, 157, 517 or 595;and the VL region comprises (a) a CDR-L1 comprising the amino acid sequence selected from any one of SEQ ID NOs:33, 178, 380, 589 or 601;(b) a CDR-L2 comprising the amino acid sequence selected from any one of SEQ ID NOs: 43, 183, 400, 590 or 602;and (c) a CDRL3 comprising the amino acid sequence selected from any one of SEQ ID NOs: 194, 416, 421, 591 or 603. 107. The polynucleotide of any of claims 100-102, 104 and 106, wherein: the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:593, 594, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:2, 5, and 157, respectively, and the VLregion comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS: 178, 183, and 194, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:1, 4, and 7, respectively, and the VLregion comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:380, 400, and 416, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:2, 5, and 10, respectively, and the VLregion comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:33, 43, and 421, respectively;384 the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:507, 513, and 517, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:589, 590, and 591, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:596, 597, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:598, 599, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;or the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:611, 612, and 613, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:614, 615, and 603, respectively. 108. The polynucleotide of any of claims 100-107, wherein the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:593, 594, and 595, respectively, and the VLregion comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively. 109. The polynucleotide of any of claims 100-102, 104, 106 and 107, wherein the Vh region is or comprises the amino acid sequence set forth in any of SEQ ID NOs: 617, 115, 256, 519, or 609;and the VL region is or comprises the amino acid sequence set forth in any of SEQ ID NOs: 618, 267, 535, 536, or 610. 110. The polynucleotide of any of claims 100-102, 104, 106, 107 and 109, wherein: the VH region is or comprises the amino acid sequence set forth in SEQ ID NO: 617;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:618 the Vh region is or comprises the amino acid sequence set forth in SEQ ID NO: 256;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:267;385 the VH region is or comprises the amino acid sequence set forth in SEQ ID NO: 519;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:535;the Vh region is or comprises the amino acid sequence set forth in SEQ ID NO: 115;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:536;or the VH region is or comprises the amino acid sequence set forth in SEQ ID NO: 609;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO:610. 111. The polynucleotide of any of claims 100-110, wherein: the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOs:593, 594, and 595, respectively;or the VH region comprises a CDRHl, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOs:611, 612, and 613, respectively;and the VL region comprises a CDR-L1, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOs:601, 602, and 603, respectively;or the VL region comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOs:614, 615, and 603, respectively. 112. The polynucleotide of any of claims 110-111, wherein the VH region is or comprises the amino acid sequence set forth in SEQ ID NO: 617;and the VLregion is or comprises the amino acid sequence set forth in SEQ ID NO: 618. 113. The polynucleotide of any of claims 100-112, wherein the fragment comprises an scFv. 114. The polynucleotide of any of claims 100-113, when the VH region and the VL region are joined by a flexible linker. 115. The polynucleotide of claim 114, wherein the scFv comprises a linker comprising the amino acid sequence GGGGSGGGGSGGGGS (SEQ ID NO:361). 116. The polynucleotide of any of claims 100-115, wherein the Vh region is aminoterminal to the VLregion. 386 117. The polynucleotide of any of claims 100-116, wherein the antigen-binding domain comprises the amino acid sequence selected from any one of SEQ ID NOs: 478, 278, 559, 560, or 442 or an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the amino acid sequence selected from any one of SEQ ID NOs: 478, 278, 559, 560, or 442. 118. The polynucleotide of any of claims 100-117, wherein the antigen-binding domain comprises the amino acid sequence set forth in SEQ ID NO: 478 or an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 478. 119. The polynucleotide of any of claims 100-118, wherein the antigen-binding domain comprises the amino acid sequence set forth in SEQ ID NO: 478. 120. The polynucleotide of any of claims 100-119, wherein the nucleic acid encoding the antigen-binding domain comprises (a) the sequence of nucleotides set forth in any of SEQ ID NOS: 648, 352, 647, 716, or 718;(b) a sequence of nucleotides that has at least 90% sequence identity to any of SEQ ID NOS: 648, 352, 647, 716, or 718;or (c) a degenerate sequence of (a) or (b). 121. The polynucleotide of any of claims 100-120, wherein the nucleic acid encoding the antigen-binding domain comprises the sequence of nucleotides set forth in any of SEQ ID NO: 460, 440, 715, 717 or 719. 122. The polynucleotide of any of claims 100-121, wherein the nucleic acid encoding the antigen-binding domain comprises the sequence of nucleotides set forth in SEQ ID NO:460. 123. The polynucleotide of any of claims 100-116, wherein the VH region is carboxyterminal to the VL region. 387 124. A polynucleotide encoding a chimeric antigen receptor, comprising a nucleic acid encoding: (1) an extracellular antigen-binding domain that specifically binds human B cell maturation antigen (BCMA), wherein the extracellular antigen-binding domain comprises: (i) a variable heavy chain (VH) comprising an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the VH region amino acid sequence set forth in SEQ ID NO: 617;and (ii) a variable light chain (Vl) region comprising an amino acid sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the VL region amino acid sequence set forth in any of SEQ ID NO: 618;(2) a spacer comprising an IgG4/2 chimeric hinge or a modified IgG4 hinge;an IgG2/4 chimeric Ch2 region;and an IgG4 Ch3 region, optionally that is about 228 amino acids in length;or a spacer set forth in SEQ ID NO: 649;(3) a transmembrane domain, optionally a transmembrane domain from a human CD28;and (4) an intracellular signaling region comprising a cytoplasmic signaling domain of a CD3-zeta (Οϋ3ζ) chain and an intracellular signaling domain of a T cell costimulatory molecule. 125. The polynucleotide of claim 124, wherein: the VH region comprises a CDR-H1, CDR-H2 and CDR-H3 contained within the VH region amino acid sequence set forth in SEQ ID NO: 617;and the VL region comprises a CDRLI, CDR-L2 and CDR-L3 contained within the Vl region amino acid sequence set forth in SEQ ID NO: 618;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:593, 594, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:596, 597, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;388 the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:598, 599, and 595, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;or the VH region comprises a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:611, 612, and 613, respectively, and the VLregion comprises a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:614, 615, and 603, respectively. 126. A polynucleotide encoding a chimeric antigen receptor, comprising a nucleic acid encoding: (1) an extracellular antigen-binding domain that specifically binds human B cell maturation antigen (BCMA), wherein the extracellular antigen-binding domain comprises: a variable heavy (VH) region comprising a CDR-H1, CDR-H2 and CDR-H3 contained within the Vh region amino acid sequence set forth in SEQ ID NO: 617;and a variable light (Vl) region comprising a CDR-L1, CDR-L2 and CDR-L3 contained within the Vl region amino acid sequence set forth in SEQ ID NO: 618;or a VH region comprising a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:593, 594, and 595, respectively, and a Vl region comprising a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;a VH region comprising a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:596, 597, and 595, respectively, and a Vl region comprising a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;a VH region comprising a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:598, 599, and 595, respectively, and a Vl region comprising a CDRLI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:601, 602, and 603, respectively;or a VH region comprising a CDR-H1, CDR-H2, and CDR-H3 comprising the amino acid sequence of SEQ ID NOS:611, 612, and 613, respectively, and a Vl region comprising a CDR389 LI, CDR-L2, and CDR-L3 comprising the amino acid sequence of SEQ ID NOS:614, 615, and 603, respectively;(2) a spacer comprising an IgG4/2 chimeric hinge or a modified IgG4 hinge;an IgG2/4 chimeric Ch2 region;and an IgG4 Ch3 region, optionally that is about 228 amino acids in length;or a spacer set forth in SEQ ID NO: 649;(3) a transmembrane domain, optionally a transmembrane domain from a human CD28;and (4) an intracellular signaling region comprising a cytoplasmic signaling domain of a CD3-zeta (Οϋ3ζ) chain and an intracellular signaling domain of a T cell costimulatory molecule. 127. The polynucleotide of any of claims 124-126, wherein the extracellular antigenbinding domain comprises the VH region amino acid sequence set forth in SEQ ID NO:617 and the VL region amino acid sequence set forth in SEQ ID NO:618. 128. The polynucleotide of any of claims 63-123, wherein the intracellular signaling region comprises an activating cytoplasmic signaling domain. 129. The polynucleotide of claim 128, wherein the activating cytoplasmic signaling domain is capable of inducing a primary activation signal in a T cell, is a T cell receptor (TCR) component and/or comprises an immunoreceptor tyrosine-based activation motif (ITAM). 130. The polynucleotide of claim 128 or claim 129, wherein the activating cytoplasmic signaling domain is or comprises a cytoplasmic signaling domain of a CD3-zeta (Εϋ3ζ) chain or a functional variant or signaling portion thereof. 131. The polynucleotide of any of claims 128-130, wherein the activating cytoplasmic domain is human or is from a human protein. 132. The polynucleotide of any of claims 124-127, 130 and 131, wherein the cytoplasmic signaling domain is or comprises the sequence set forth in SEQ ID NO:628 or a sequence of amino acids that has at least 90% sequence identity to SEQ ID NO:628. 390 133. The polynucleotide of any of claims 124-127 and 130-132, wherein the nucleic acid encoding the cytoplasmic signaling domain is or comprises the sequence set forth in SEQ ID NO :627 or is a codon-optimized sequence and/or degenerate sequence thereof. 134. The polynucleotide of any of claims 124-127 and 130-133, wherein the nucleic acid encoding the cytoplasmic signaling domain is or comprises the sequence set forth in SEQ ID NO:652. 135. The polynucleotide of any of claims 128-134, wherein the intracellular signaling region further comprises a costimulatory signaling region. 136. The polynucleotide of claim 135, wherein the costimulatory signaling region comprises an intracellular signaling domain of a T cell costimulatory molecule or a signaling portion thereof. 137. The polynucleotide of claim 124-127, 135 and 136, wherein the costimulatory signaling region comprises an intracellular signaling domain of a CD28, a 4-IBB or an ICOS or a signaling portion thereof. 138. The polynucleotide of any of claims 124-127 and 135-137, wherein the costimulatory signaling region comprises an intracellular signaling domain of 4-IBB. 139. The polynucleotide of any of claims 124-127 and 135-138, wherein the costimulatory signaling region is human or is from a human protein. 140. The polynucleotide of any of claims 124-127 and 135-139, wherein the costimulatory signaling region is or comprises the sequence set forth in SEQ ID NO:626 or a sequence of amino acids that exhibits at least 90% sequence identity to the sequence set forth in SEQ ID NO: 626. 391 141. The polynucleotide of any of claims 124-127 and 135-140, wherein the nucleic acid encoding the costimulatory region is or comprises the sequence set forth in SEQ ID NO:625 or is a codon-optimized sequence and/or degenerate sequence thereof. 142. The polynucleotide of any of claims 124-127 and 135-141, wherein the nucleic acid encoding the costimulatory signaling region comprises the sequence set forth in SEQ ID NO:681. 143. The polynucleotide of any of claims 63-139, wherein the intracellular signaling region comprises the sequence set forth in SEQ ID NO:628 or a sequence of amino acids that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO:628 and the sequence set forth in SEQ ID NO:626 or a sequence of amino acids that exhibits at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the sequence set forth in SEQ ID NO: 626. 144. The polynucleotide of any of claims 63-139 and 143, wherein the intracellular signaling region is or comprises the sequences set forth in SEQ ID NO:628 and SEQ ID NO:626. 145. The polynucleotide of any of claims 124-127, 135-137, 139 and 144, wherein the costimulatory signaling region comprises an intracellular signaling domain of CD28. 146. The polynucleotide of any of claims 63-139 and 145, wherein the intracellular signaling region comprises the sequence set forth in SEQ ID NO :628 or a sequence of amino acids that has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO:628 and the sequence set forth in SEQ ID NO:680 or a sequence of amino acids that exhibits at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the sequence set forth in SEQ ID NO: 680. 147. The polynucleotide of any of claims 63-139, 145 and 146, wherein the intracellular signaling region is or comprises the sequences set forth in SEQ ID NO:628 and SEQ ID NO:680. 392 148. The polynucleotide of any of claims 135-147, wherein the costimulatory signaling region is between the transmembrane domain and the intracellular signaling region. 149. The polynucleotide of any of claims 63-148, wherein the transmembrane domain is or comprises a transmembrane domain from CD4, CD28, or CD8. 150. The polynucleotide of claim 149, wherein the transmembrane domain is or comprises a transmembrane domain from a CD28. 151. The polynucleotide of any of claims 63-150, wherein the transmembrane domain is human or is from a human protein. 152. The polynucleotide of any of claims 63-151, wherein the transmembrane domain is or comprises the sequence set forth in SEQ ID NO:624 or a sequence of amino acids that exhibits at least 90% sequence identity to SEQ ID NO:624. 153. The polynucleotide of any of claims 63-152, wherein the nucleic acid encoding the transmembrane domain is or comprises the sequence set forth in SEQ ID NO:623 or is a codon-optimized sequence and/or degenerate sequence thereof. 154. The polynucleotide of claim 153, wherein the nucleic acid encoding the transmembrane domain comprises the sequence set forth in SEQ ID NO:688. 155. The polynucleotide of any of claims 63-154, wherein the encoded chimeric antigen receptor comprises from its N to C terminus in order: the antigen-binding domain, the spacer, the transmembrane domain and the intracellular signaling region. 156. The polynucleotide of any of claims 63-155, wherein the polynucleotide further encodes a truncated receptor. 393 157. The polynucleotide of any of claims 63-156, wherein the binding of the encoded antigen-binding domain and/or the encoded chimeric antigen receptor, or a measure indicative of function or activity of the encoded chimeric antigen receptor following exposure to cells expressing surface BCMA, is not reduced or blocked or is not substantially reduced or blocked in the presence of a soluble or shed form of BCMA. 158. The polynucleotide of claim 157, wherein the concentration or amount of the soluble or shed form of the BCMA corresponds to a concentration or amount present in serum or blood or plasma of the subject or of a multiple myeloma patient, or on average in a patient population for the disease or disorder, or at a concentration or amount of the soluble or shed BCMA at which the binding or measure is reduced or blocked, or is substantially reduced or blocked, for cells expressing a reference anti-BCMA recombinant receptor, optionally a reference anti-BCMA CAR, in the same assay. 159. The polynucleotide of any of claims 63-158, wherein the polynucleotide comprises the sequence set forth in any of SEQ ID NOS: 751-756 or a sequence that exhibits at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the sequence set forth in any of SEQ ID NOS: 751-756 and the encoded receptor retains the function to bind to BCMA and retains the reduced RNA heterogeneity. 160. The polynucleotide of any of claims 63-159, wherein the polynucleotide comprises the sequence set forth in any of SEQ ID NOS: 755 and 756 or a sequence that exhibits at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to the sequence set forth in any of SEQ ID NOS: 755 and 756 and the encoded receptor retains the function to bind to BCMA and retains the reduced RNA heterogeneity. 161. The polynucleotide of any of claims 63-160, wherein the polynucleotide comprises the sequence set forth in SEQ ID NOs:755 or a sequences that exhibits at least or at least about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity thereto and the encoded receptor retains the function to bind to BCMA and retains the reduced RNA heterogeneity. 394 162. The polynucleotide of any of claims 63-161, wherein the polynucleotide comprises the sequence set forth in SEQ ID NOs:755 and the encoded receptor retains the function to bind to BCMA and retains the reduced RNA heterogeneity. 163. A vector comprising the polynucleotide of any of claims 63-162. 164. The vector of claim 163, wherein the vector is a viral vector. 165. The vector of claim 164, wherein the viral vector is a retroviral vector. 166. The vector of claim 164 or claim 165, wherein the viral vector is a lentiviral vector. 167. A chimeric antigen receptor encoded by the polynucleotide of any of claims 63162. 168. An engineered cell, comprising the chimeric antigen receptor of any of claims 162 and 167. 169. An engineered cell, comprising the polynucleotide of any of claims 63-162 or the vector of any of claims 163-166. 170. The engineered cell of claim 168 or claim 169, wherein the cell is an immune cell. 171. The engineered cell of any of claims 168 wherein the immune cell is a primary cell obtained from a subject. 172. The engineered cell of claim 170 or claim 171, wherein the immune cell is an NK cell or a T cell. 395 173. The engineered cell of any of claims 170-172, wherein the immune cell is a T cell and the T cell is a CD4+ and/or CD8+ T cell. 174. The engineered cell of any of claims 168-173, wherein the cell comprises transcribed RNA encoding the chimeric antigen receptor, optionally messenger RNA (mRNA), that exhibits at least 70%, 75%, 80%, 85%, 90%, or 95% RNA homogeneity. 175. The engineered cell of any of claims 168-174, wherein the cell comprises transcribed RNA encoding the chimeric antigen receptor, optionally messenger RNA (mRNA), that exhibits reduced heterogeneity compared to the heterogeneity of transcribed mRNA in a cell encoding a reference chimeric antigen receptor, said reference chimeric antigen receptor comprising the same amino acid sequence as the chimeric antigen receptor but encoded by a different polynucleotide sequence comprising one or more nucleotide differences in the polynucleotide encoding the CARs and/or in which the reference chimeric antigen receptor is encoded by a polynucleotide comprising one or more splice donor site and/or one or more splice acceptor site in the nucleic acid encoding the spacer. 176. The engineered cell of claim 175, wherein the RNA heterogeneity is reduced by greater than or greater than about 10%, 15%, 20%, 25%, 30%, 40%, 50% or more. 177. The engineered cell of claim 175 or claim 176, wherein the polynucleotide encoding the reference CAR comprises transcribed RNA encoding the reference CAR, optionally messenger RNA (mRNA), that exhibits greater than or greater than about 10%, 15%, 20%, 25%, 30%, 40%, 50% or more RNA heterogeneity. 178. The engineered cell of any of claims 174-177, wherein the RNA homogeneity and/or heterogeneity is determined by agarose gel electrophoresis, chip-based capillary electrophoresis, analytical ultracentrifugation, field flow fractionation, or liquid chromatography. 179. The engineered cell of any of claims 168-178, wherein, among a plurality of the engineered cells, less than or less than about 10%, 9%, 8%, 7%, 5%, 4%, 3%, 2% or 1% of the 396 cells in the plurality comprise a chimeric antigen receptor that exhibits tonic signaling and/or antigen independent activity or signaling. 180. A composition comprising the chimeric antigen receptor of any one of claims 162 and 167, the polynucleotide of any of claims 63-162, or the vector of any of claims 163-166 . 181. A composition comprising the engineered cell of any one of claims 168-179. 182. The composition of claim 181, wherein the composition comprises CD4+ and CD8+ T cells and the ratio of CD4+ to CD8+ T cells is from or from about 1:3 to 3:1. 183. The composition of any of claims 180-182, further comprising a pharmaceutically acceptable excipient. 184. A method of treatment, comprising administering the engineered cell of any of claims 168-179 or the composition of any of claims 180-183 to a subject having a disease or disorder. 185. The method of claim 184, wherein the method comprises administering a dose of the engineered cells or a composition comprising a dose of the engineered cells. 186. Use of the engineered cell of any of claims 168-179 or the composition of any of claims 180-183 for the manufacture of a medicament for the treatment of a disease or disorder. 187. Use of the engineered cells of any of claims 168-179 or the composition of any of claims 180-183 for treating a disease or disorder. 188. The use of claim 186 or claim 187, wherein the engineered cells or the composition are for use in a treatment regimen, wherein the treatment regimen comprises administering a dose of the engineered cells or a composition comprising a dose of the engineered cells. 397 189. The method of claim 184 or claim 185 or the use of any of claims 186-188, wherein the disease or disorder is associated with expression of B cell maturation antigen (BCMA), optionally a B cell-related disorder. 190. The method or the use of any of claims 184-189, wherein the disease or disorder associated with BCMA is an autoimmune disease or disorder. 191. The method or the use of any one of claims 185-190, wherein the disease or disorder associated with BCMA is a cancer. 192. The method or the use of claim 191, wherein the cancer is a BCMA-expressing cancer. 193. The method or the use of claim 191 or claim 192, wherein the cancer is a B cell malignancy. 194. The method or the use of any one of claims 191-193, wherein the cancer is a lymphoma, a leukemia, or a plasma cell malignancy. 195. The method or the use of claim 194, wherein the cancer is a lymphoma and the lymphoma is Burkitt’s lymphoma, non-Hodgkin’s lymphoma (NHL), Hodgkin’s lymphoma, Waldenstrom macroglobulinemia, follicular lymphoma, small non-cleaved cell lymphoma, mucosa-associated lymphatic tissue lymphoma (MALT), marginal zone lymphoma, splenic lymphoma, nodal monocytoid B cell lymphoma, immunoblastic lymphoma, large cell lymphoma, diffuse mixed cell lymphoma, pulmonary B cell angiocentric lymphoma, small lymphocytic lymphoma, primary mediastinal B cell lymphoma, lymphoplasmacytic lymphoma (LPL), or mantle cell lymphoma (MCL). 196. The method or the use of claim 195, wherein the cancer is a leukemia and the leukemia is chronic lymphocytic leukemia (CLL), plasma cell leukemia or acute lymphocytic leukemia (ALL). 398 197. The method or the use of claim 194, wherein the cancer is a plasma cell malignancy and the plasma cell malignancy is multiple myeloma (MM) or plasmacytoma. 198. The method or the use of any of claims 191-194 and 197, wherein the cancer is multiple myeloma (MM). 199. The method or the use of any of claims 185 and 188-198, wherein the dose of ד׳engineered T cells comprises between at or about 1x10 CAR-expressing T cells and at or about 2 x 109 CAR-expressing T cells or between at or about. 200. The method or the use of any of claims 185 and 188-199, wherein the dose of ד׳engineered T cells comprise between at or about 2.5 x 10 CAR-expressing T cells and at or 97 about 1.2 x 10 CAR-expressing T cells, between at or about 5.0 x 10 CAR-expressing T cells 88 and at or about 4.5 x 10 CAR-expressing T cells, or between at or about 1.5 x 10 CARQ expressing T cells and at or about 3.0 x 10 CAR-expressing T cells. 201. The method or the use of any of claims 185 and 188-200, wherein the dose of 7 78 engineered T cells comprise at or about 2.5 x 10 , at or about 5.0 x 10 , at or about 1.5 x 10 , at or about 3.0 x 108, at or about 4.5 x 108, at or about 8.0 x 108 or at or about 1.2 x 109 CARexpressing T cells. 202. The method or the use of any of claims 185 and 188 , wherein the dose of 7 88 engineered T cells comprise at or about 5.0 x 10 , at or about 1.5 x 10 , at or about 3.0 x 10 or at Q or about 4.5 x 10 CAR-expressing T cells. 203. The method or the use of any of claims 185 and 188-202, wherein the dose of engineered T cells comprises a combination of CD4+ T cells and CD8+ T cells, at a ratio of CD4+ CAR-expressing T cells to CD8+ CAR-expressing T cells and/or of CD4+ T cells to CD8+ T cells, that is or is approximately 1:1 or is between approximately 1:3 and approximately 3:1. 204. The method or the use of any of claims 185 and 188-203, wherein less than about 25%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2% or 1% of the CAR-expressing T cells 399 in the dose of engineered T cells express a marker of apoptosis, optionally Annexin V or active Caspase 3. 205. The method or the use of any of claims 185 and 188-204 , wherein less than 5%, 4%, 3%, 2% or 1% of the CAR-expressing T cells in the dose of engineered T cells express Annexin V or active Caspase 3. 206. The method or the use of any of claims 184, 185, and 188-205, wherein prior to the administration, the subject has received a lymphodepleting therapy comprising the administration of fludarabine at or about 20-40 mg/m body surface area of the subject, optionally at or about 30 mg/m , daily, for 2-4 days, and/or cyclophosphamide at or about 200400 mg/m body surface area of the subject, optionally at or about 300 mg/m , daily, for 2-4 days. 207. The method or the use of any of claims 184, 185, and 188-206 , wherein the subject has received a lymphodepleting therapy comprising the administration of fludarabine at or about 30 mg/m body surface area of the subject, daily, and cyclophosphamide at or about 300 2 mg/m body surface area of the subject, daily, for 3 days. 208. The method or the use of any of claims 184, 185, and 188-207 , wherein at or prior to the administration of the dose of cells, the subject has received three or more prior therapies for the disease or disorder, optionally four or more prior therapies, optionally selected from among: autologous stem cell transplant (ASCT);an immunomodulatory agent;a proteasome inhibitor;and an anti-CD38 antibody. 209. The method or the use of any of claim 208, wherein the immunomodulatory agent is selected from among thalidomide, lenalidomide and pomalidomide. 400 210. The method or the use of claim 208 or claim 209, wherein the proteasome inhibitor is selected from among bortezomib, carfilzomib and ixazomib. 211. The method or the use of any of claims 208-210, wherein the anti-CD38 antibody is or comprises daratumumab. 212. The method or the use of any of claims 184, 185, and 188-211, wherein at the time of the administration of the dose of cells, and/or at the time of lymphodepleting chemotherapy or leukapheresis, the subject has not had active or history of plasma cell leukemia (PCL). 213. The method or the use of any of claims 184, 185, and 188-212, wherein at the time of the administration of the dose of cells the subject has developed secondary plasma cell leukemia (PCL). 214. The method or use of any of claims 184, 185, and 188-213, wherein, at the time of administration, the subject: has relapsed or been refractory following at least 3 or at least 4 prior therapies for multiple myeloma;is an adult subject or is 25 or 35 years of age or older;has a time from diagnosis of multiple myeloma of approximately 4 years or between 2 and 15 or 2 and 12 years;has received about 10 or between 3 and 15 or between 4 and 15 prior regimens for multiple myeloma;has been refractory to or not responded to bortezomib, carfilzomib, lenalidomide, pomalidomide and/or an anti-CD38 monoclonal antibody;has had prior autologous stem cell transplant or has not had prior autologous stem cell transplant;and/or has IMWG high risk cytogenetics. 215. The method or the use of any of claims 184-214, wherein the method is capable of achieving a specified response or outcome , optionally at a designated timepoint following 401 initiation of the administration, in at least one or in at least 10 %, at least 20 %, at least 30 %, at least 40 %, at least 50%, 60%, 70%, 80%, 90%, or 95% of subjects in a cohort of subjects having the disease or disorder of the subject, optionally wherein the cohort of subjects has at least the same number of prior therapies, prognosis or prognostic factor, sub-type, secondary involvement or other specified patient characteristic or characteristics, as the subject treated by the method, wherein: the response is selected from the group consisting of objective response (OR), complete response (CR), stringent complete response (sCR), very good partial response (VGPR), partial response (PR) and minimal response (MR);the response or outcome is or comprises an OR the response or outcome is or comprises a CR. 216. The method or the use of claim 215, wherein the response or outcome is an OR and is achieved in at least 40 %, at least 50 %, at least 60 %, at least 70 %, or at least 80 % of subjects of the cohort. 217. The method or the use of claim 215, wherein the response or outcome is a CR or sCR and is achieved in at least 20 %, 30 %, or 40 % of subjects of the cohort. 218. The method or use of any of claims 215-217, wherein the dose of cells is less than 1.5 x 10A8 cells or less than 1.5 x 10A8 CAR+ T cells or less than 3 x 10A8 CAR+ T cells or less than 4.5 x 10A8 CAR+ T cells. 219. The method or use of any of claims 215-217, wherein the dose of cells is at or less than 1.5 x 10A8 cells or less than 1.5 x 10A8 CAR+ T cells. 220. The method or use of any one of claims 215-219, wherein the dose of cells at or about 5 x 107 cells or CAR+ T cells. 221. The method or use of any one of claims 215-219, wherein the dose of cells at or about 1.5 x 108 cells or CAR+ T cells. 402 222. The method or use of any one of claims 215-219, wherein the dose of cells at or about 3 x 108 cells or CAR+ T cells. 223. The method or use of any one of claims 215-219, wherein the dose of cells at or about 4.5 x 108 cells or CAR+ T cells. 224. The method or use of any one of claims 215-223, wherein the response or outcome comprises or further comprises the absence of grade 3 or higher, or grade 4 or higher, neurotoxicity, the absence of grade 3 or higher, or grade 4 or higher, cytokine release syndrome. 225. The method or the use of any of claims 215-224, wherein the dose of engineered 7 8 8 T cells comprise at or about 5.0 x 10 , at or about 1.5 x 10 , at or about 3.0 x 10 or at or about 4.5 x 108 CAR-expressing T cells. 226. The method or the use of any of claims 215-225, wherein the dose of the ד׳engineered T cells comprise at or about 5.0 x 10 CAR-expressing T cells. 227. The method or the use of any of claims 215-225, wherein the dose of the Q engineered T cells comprise at or about 1.5 x 10 CAR-expressing T cells. 228. The method or the use of any of claims 215-225, wherein the dose of the Q engineered T cells comprise at or about 3x10 CAR-expressing T cells. 229. The method or the use of any of claims 215-225, wherein the dose of the Q engineered T cells comprise at or about 4.5 x 10 CAR-expressing T cells. 230. The cell of any of claims 168-179 or composition of any of claims 180-183, wherein the cell or composition, following administration at a dose of CAR+ cells is capable of achieving, optionally at a designated time following initiation of the administration, a specified response or outcome in at least one of, or in at least 10 %, at least 20 %, at least 30 %, at least 40 %, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% of subjects 403 within a cohort of subjects or evaluable subjects thereof, wherein the cohort of subjects is a cohort having multiple myeloma. 231. The cell or composition of claim 230, wherein the achievement of the response or outcome is at the designated time following initiation of administration, which is at 1, 2, 3, 6, 9, or 12 months following said initiation. 232. The cell or composition of claim 231, wherein the achievement of the response or outcome is at the designated time following initiation of administration, which is at 1 or 2 or 3 months following said initiation. 233. The cell or composition of claim 230, wherein: the cohort of subjects is subjects having relapsed or refractory multiple myeloma;the cohort of subjects is subjects having relapsed or refractory multiple myeloma having been adminiseterd, and relapsed or been refractory following, at least 3 prior therapies for multiple myeloma, said prior therapies optionally including an immunomodulatory agent;a proteasome inhibitor;and/or an anti-CD38 antibody;the cohort of subjects is subjects having relapsed or refractory multiple myeloma having been adminiseterd, and relapsed or been refractory following, at least 3 prior therapies for multiple myeloma, said prior therapies optionally including an immunomodulatory agent;a proteasome inhibitor;and/or an anti-CD38 antibody and/or an autologous stem cell transplant;and/or the cohort of subjects is subjects has no active plasma cell leukemia (PCL) or no history of PCL at the time of said administration;the cohort of subjects is subjects has developed secondary plasma cell leukemia (PCL) prior to administration of the cells the cohort of subjects is or includes subjects having relapsed or refractory multiple myeloma having been adminiseterd, and relapsed or been refractory following, at least 4 or an average of at least 10 prior therapies for multiple myeloma;the cohort of subjects consists of or includes adult subjects;the cohort of subjects has a median time from diagnosis of 4 years and/or a range of time from diagnostis from 2 to 12 years;404 the cohort of subjects has received a median of 10 prior regimens or between 3 and 15 or 4 and 15 prior therapies for multiple myeloma;the cohort of subjects includes subjects refractory to bortezomib, carfilzomib, lenalidomide, pomalidomide and an anti-CD38 monoclonal antibody;the cohort of subjects includes subjects having had prior autologous stem cell transplant;and/or the cohort of subjects includes subjects having IMWG high risk cytogenetics. 234. The cell or composition of claim 233, wherein the immunomodulatory agent is selected from among thalidomide, lenalidomide and pomalidomide, the proteasome inhibitor is selected from among bortezomib, carfilzomib and ixazomib, and/or the anti-CD38 antibody is or comprises daratumumab. 235. The cell or composition of any one of claims 230 to 234, wherein the response or outcome is selected from the group consisting of objective response (OR), complete response (CR), stringent complete response (sCR), very good partial response (VGPR), partial response (PR) and minimal response (MR), optionally based on the International Myeloma Working Group (IMWG) uniform response criteria;the response or outcome is or comprises an OR, optionally based on the International Myeloma Working Group (IMWG) uniform response criteria;or the response or outcome is or comprises a CR, optionally based on the International Myeloma Working Group (IMWG) uniform response criteria. 236. The cell or composition of any one of claims 230 to 235, wherein the response or outcome is or comprises an OR. 237. The cell or composition of any one of claims 230 to 236, wherein the dose is capable of achieving the response or outcome in at least 40 %, at least 50 %, at least 60 %, at least 70 %, or at least 80 % of subjects of the cohort. 238. The cell or composition of any of claims 230 to 235, wherein the response or outcome is or comprises a CR or sCR. 405 239. The cell or composition of any one of claims 230 to 238, wherein the dose is capable of achieving the response or outcome in at least 20 %, 30 %, or 40 % of subjects of the cohort. 240. The cell or composition of any one of claims 230 to 239, wherein the dose capable of achieving said response or outcome is less than 1.5 x 10A8 cells the dose capable of achieving said response or outcome is less than 1.5 x 10A8 CAR+ T cells. 241. The cell or composition of any one of claims 230 to 240, wherein the dose capable of achieving said response or outcome is less than 1.5 x 10A8 cells the dose capable of achieving said response or outcome is less than 1.5 x 10A8 CAR+ T cellsthe dose capable of achieving said response or outcome is less than 3 x 10A8 CAR+ T cells;or the dose capable of achieving said response or outcome is less than or less than 4.5 x 10A8 CAR+ T cells. 242. The cell or composition of any one of claims 230 to 241, wherein the dose capable of achieving said response or outcome is less than 1 x 10A8 cells the dose capable of achieving said response or outcome is less than 1 x 10A8 CAR+ T cells. 243. The cell or composition of any one of claims 230 to 242, wherein the dose capable of achieving said response or outcome is at or about 5 x 10A7 cells or at or about 5 x 10A7 CAR+ T cells. 244. The cell or composition of any one of claims 230 to 243, wherein the dose capable of achieving said response or outcome is at or about 1.5 x 10A8 cells or CAR+ T cells. 245. The cell or composition of any one of claims 230 to 244, wherein the dose capable of achieving said response or outcome is at or about 3 x 10A8 cells or CAR+ T cells. 406 246. The cell or composition of any one of claims 230 to 245, wherein the dose capable of achieving said response or outcome is at or about 4.5 x 10A8 cells or CAR+ T cells. 247. The cell or composition of any one of claims 230 to 246, wherein the response or outcome comprises or further comprises the absence of grade 3 or higher, or grade 4 or higher, neurotoxicity, the absence of grade 3 or higher, or grade 4 or higher, cytokine release syndrome. 248. A method of determining the heterogeneity of a transcribed nucleic acid of a transgene, the method comprising: a) amplifying a transcribed nucleic acid using at least one 5' and 3' primer pair, wherein at least one pair comprises a 5' primer that is complementary to a nucleic acid sequence within the 5' untranslated region (5' UTR) of the transcribed nucleic acid and a 3' primer that is complementary to a nucleic acid sequence within the 3' untranslated region (3' UTR) of the transcribed nucleic acid to generate one or more amplified products;and b) detecting the amplified products, wherein the presence of two or more amplified products from at least one 5' and 3' primer pair indicates heterogeneity in the amplified products. 249. The method of claim 248 wherein the detected differences in b) are different lengths of the amplified transcripts. 250. The method of claim 248 wherein the differences in b) are differences in chromatographic profiles of the amplified transcripts. 251. The method of any of claims 248-250, wherein the differences in the amplified products are determined by agarose gel electrophoresis, chip-based capillary electrophoresis, analytical ultracentrifugation, field flow fractionation, or chromatography. 252. The method of any of claims 248-251, wherein the 5' primer is specific to sequence transcribed from the promoter region of the transcribed nucleic acid. 407 253. The method of any of claims 248-252, wherein the transcribed nucleic acid is amplified using a 3' primer specific to a sequence within the amino acid-coding sequence of the polynucleotide, and/or the 3' untranslated region of the transcribed pre-mRNA. 254. The method of any of claims 248-253, wherein the 3 primer is specific to the polyadenylation sequence or enhancer region of the 3' untranslated region of the transcribed premRNA. 255. The method of any of claims 248-254, wherein step a) is effected by a single amplification reaction, using a single 5' and 3' primer pair comprising a 5' primer that is complementary to a nucleic acid sequence within the 5' untranslated region (5' UTR) of the transcribed nucleic acid and a 3' primer that is complementary to a nucleic acid sequence within the 3' untranslated region (3' UTR). 256. The method of any of claims 248-255, wherein step a) is effected by parallel or subsequent amplification reactions using a first 5' and 3' primer pair, a second 5' and 3'primer pair, and optionally additional 5' and 3'primer pairs, wherein: the first 5' and 3'primer pair contains a 5' primer that is complementary to a nucleic acid sequence within the 5' UTR of the transcribed nucleic acid and a 3' primer that is complementary to a nucleic acid sequence within the 3' UTR of the transcribed nucleic acid;the second 5' and 3' primer pair contains a 5' primer whose sequence is complementary to a portion of the translated sequence of the nucleic acid transcript and a 3' primer whose sequence is complementary to a nucleic acid sequence within the 3' UTR of the transcript;and the optionally additional 5' and 3'primer pairs each contain sequences complementary to sequences within the translated region of the transcript. 257. The method of claim 256, wherein the parallel or subsequent amplification reactions amplify overlapping portions of the transcript. 258. The method of any of claims 248-257, wherein the amplified products are predicted to be about 1.5 kilobases, 2 kilobases, 2.5 kilobases, 3 kilobases, 3.5 kilobases, 408 4 kilobases, 4.5 kilobases, 5 kilobases, 5.5 kilobases, 6 kilobases, 7 kilobases, or 8 kilobases in length. 259. The method of any of claims 248-258, wherein a transcribed nucleic acid that is detected as having heterogeneity is identified as a transgene candidate for removal of one or more splice site. 260. The method of claim 259, wherein the transcribed nucleic acid of the transgene candidate exhibits at least or at least about 5%, 10%, 15%, 20%, 25%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or more heterogeneity following expression in a cell. 261. A method of reducing the heterogeneity of an expressed transgene transcript, the method comprising: a) identifying a transgene candidate for the removal of splice sites according to the method of claim 259 or claim 260;b) identifying one or more potential splice donor and/or splice acceptor sites;and c) modifying the nucleic acid sequence at or near the one or more potential splice donor and/or splice acceptor sites identified in b), thereby generating a modified polynucleotide. 262. The method of claim 261, further comprising: d) assessing the transgene candidacy for the removal of splice sites as in step a). 263. The method of claim 262, further comprising e) repeating steps b)-d) until the heterogeneity of the transcript in step d) is reduced compared to the heterogeneity of the transcript as determined in step a). 264. The method of any of claims 261-263, wherein the one or more potential splice donor and/or splice acceptor sites exhibit a score about or at least about 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, or 1.0 of a splice event, and/or is/are predicted to be involved in a splice event with a probability of at least 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100%. 409 265. The method of any of claims 261-264, wherein splice donor sites and splice acceptor sites are identified independently. 266. The method of any of claims 261-265, wherein the splice acceptor and/or donor site(s) is/are canonical, non-canonical, and/or cryptic splice acceptor and/or donor site(s). 267. The method of any of claims 261-266, wherein the transgene is a chimeric antigen receptor or a portion of a chimeric antigen receptor. 268. The method of claim 267, wherein the CAR polypeptide comprises an antigenbinding domain comprising an antibody fragment, optionally a single chain antibody fragment (scFv), comprising a variable heavy chain (Vh) and a variable light chain (Vl), a spacer, a transmembrane region, and an intracellular signaling region. 269. The method of claim 267 or claim 268, wherein the modified polynucleotide is not modified within the coding sequence for the antigen-binding domain of the encoded CAR polypeptide. 270. The method of any of claims 261-269, wherein the encoded amino acid sequence of the transgene is unchanged following modification of the polynucleotide. 271. The method of any of claims 261-270, wherein the RNA transcribed from the modified polynucleotide exhibits at least or at least about 70%, 75%, 80%, 85%, 90%, or 95% homogeneity following expression of the unmodified polynucleotide in a cell. 272. The method of any of claims 248-271, wherein the cell is a human cell. 273. The method of any of claims 248-272, wherein the cell is a T-cell. 274. The method of any of claims 248-273, wherein the method is a computer implemented method, and wherein one or more steps a)-c) occur at an electronic device comprising one or more processors and memory. 410 275. A computer system comprising a processor and memory, the memory comprising instructions operable to cause the processor to carry out any one or more of steps of the methods of any of claims 248-274. 411