Isolation and Characterization of Prostrate Antigen Specific High Affinity TCR

Medical University Of South Carolina, Charleston SC

Investigators

Linked publications & trials

Abstract

DESCRIPTION (provided by applicant): A key factor that has so far limited the efficacy of immunotherapy for prostate cancer patients is the poor immunogenicity of TAA expressed by prostate cancer cells. This poor immunogenicity is likely due to immunologic tolerance to antigens expressed by normal cells of the prostate. As a result, the development of therapeutic vaccines and adoptive T cell transfer approaches for treating prostate cancer has made little progress over the years. The studies outlined in this application take advantage of a gene therapy approach that is capable of redirecting the specificity of normal peripheral blood T cells to recognize tumor cells. We will take advantage of the fact that the antigenic peptides expressed by prostate cancer cells that are targeted by our T cells need not be immunogenic in prostate cancer patients since we would be providing them their own T cells engineered to recognize their tumors. Given that women lack prostate glands, their T cells should not be tolerant to prostate cancer antigens. Furthermore, their T cells may express T cell receptors with higher affinity for prostate cancer antigens than similar T cells in men. Therefore, this application proposes to isolate prostate cancer reactive T cell clones from the PBL of women. We will then identify and clone the T cell receptors from these prostate cancer reactive T cells and construct retroviral vectors capable of engineering normal PBL-derived T cells to recognize prostate cancer cells. We will then evaluate these TCR transduced T cells for their efficacy in vitro and in vivo. While this application applies existing technologies and established immunologic concepts to the development of new treatments for prostate cancer patients, we believe the unorthodox source of T cells adds a novel twist to this study. In addition to the potential for a new treatment option for prostate cancer patients, this study will increase our understanding of tolerance to prostate cancer antigens that may assist those in developing new prostate cancer vaccines. PUBLIC HEALTH RELEVANCE: This proposal is to isolate T cell clones bearing high affinity T cells receptors (TCR) reactive with prostate specific membrane antigen (PSMA) and prostate stem cell antigen (PSCA) and to characterize their efficacy after engineering them on normal peripheral blood T cells to recognize prostate cancer cells. The strength of our proposal is its innovative hypothesis that prostate antigen reactive T cells isolated from normal adult females would have higher avidity and express higher affinity TCRs than similar T cells isolated from males. On successful completion of this project we hope to circumvent immunologic tolerance in patients with local and advanced prostate cancer by providing them with their own T cells engineered with high affinity TCR to recognize and kill their tumors.