Targeting Mechanisms of GUCY2C-specific Tolerance for Cancer Immunotherapy
Identifying T cell receptors (TCRs) targeting self-antigens is necessary to define tolerance mechanisms limiting immunity to self-antigensand may provide opportunities for effective cancer immunotherapy. However, the diversity of TCRs and low abundance of antigen-specific clones (<10-100 cells/organism) make identification of individual TCRs difficult. Moreover, tolerance further limits self-reactive TCR abundance. Here, we define a process to identify TCRs recognizing the intestinal antigen GUCY2C, an emerging target in cancer therapy. GUCY2C-specific CD4+T cells were purified from immunized GUCY2C -/-mice, where they develop in the absence of tolerance. Next-generation sequencingof TCR transcripts identifiedindividual GUCY2C-specific TCRs. GUCY2C recognition by CD4+T cells engineered to express identified TCRs in vitro confirmed TCR specificity and activity. Further, reconstitution of mice with TCR “retrogenic” hematopoietic stem cells (HSCs)resulted in normal CD4+T-cell development, responsiveness to immunization, and GUCY2C-induced tolerance. Therefore, this approach identifies GUCY2C-specific TCRs that may be employed for mapping self-tolerance mechanismsto identify novelcancer immunotherapies, accelerating therapeutic discovery.^
Abraham, Tara, "Targeting Mechanisms of GUCY2C-specific Tolerance for Cancer Immunotherapy" (2018). ETD Collection for Thomas Jefferson University. AAI13420004.