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Optimizing T‐cell receptor avidity with somatic hypermutation
Author(s) -
Bassan David,
Gozlan Yosi Meir,
SharbiYunger Adi,
Tzehoval Esther,
Eisenbach Lea
Publication year - 2019
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.32612
Subject(s) - somatic hypermutation , avidity , t cell receptor , adoptive cell transfer , immunotherapy , antigen , biology , t cell , immunology , cancer research , central tolerance , streptamer , immune tolerance , antibody , immune system , b cell
Adoptive transfer of T cells that have been genetically modified to express an antitumor T‐cell receptor (TCR) is a potent immunotherapy, but only if TCR avidity is sufficiently high. Endogenous TCRs specific to shared (self) tumor‐associated antigens (TAAs) have low affinity due to central tolerance. Therefore, for effective therapy, anti‐TAA TCRs with higher and optimal avidity must be generated. Here, we describe a new in vitro system for directed evolution of TCR avidity using somatic hypermutation (SHM), a mechanism used in nature by B cells for antibody optimization. We identified 44 point mutations to the Pmel‐1 TCR, specific for the H‐2D b ‐gp100 25‐33 melanoma antigen. Primary T cells transduced with TCRs containing two or three of these mutations had enhanced activity in vitro . Furthermore, the triple‐mutant TCR improved in vivo therapy of tumor‐bearing mice, which exhibited improved survival, smaller tumors and delayed or no relapse. TCR avidity maturation by SHM may be an effective strategy to improve cancer immunotherapy.