IDENTIFICATION OF A T-CELL RECEPTOR FROM A THERAPEUTIC MURINE T-CELL CLONE

Tumor-infiltrating lymphocytes (TIL) have been successfully used for t he treatment of metastatic malignancies in clinical trials and in expe rimental animal models. Tumor-specific reactivity by TIL is mediated v ia receptors expressed on the surface of T cells (TcRs), which recogni ze tumor-associated antigens (TAA) presented in the context of MHC mol ecules on the surface of tumor cells. The current study was performed to identify the TcR alpha and beta chains from a tumor-specific therap eutic TIL clone that can be used to develop a preclinical animal model for genetically modifying lymphocytes and hematopoietic progenitors w ith TcR genes. TIL 205 was generated from a subcutaneous implant of MC A-205 fibrosarcoma and at 21 days was cloned by Limiting dilution. TIL clone 8, obtained from a culture seeded at one cell/well, mediated sp ecific lysis and specific secretion of gamma-interferon to MCA-205 and WP6, a subclone of MCA 205. No reactivity was observed against other syngeneic sarcoma lines. Anchor polymerase chain reaction analysis det ermined that antigen recognition by clone 8 was mediated by a TcR cons isting of V alpha 3/J alpha 27 and V beta 8.2/D beta 2.1/D beta 2.4. I mmunofluorescent staining with V beta subfamily specific monoclonal an tibodies revealed that >95% of the T cells in TIL clone 8 expressed V beta 8.2, confirming that TIL clone 8 was indeed a clone. In contrast, -30% of the T cells in the parental TIL 205 expressed V beta 8.2. The transfer of as few as 500,000 TIL clone 8 cells in conjunction with t he systemic administration of recombinant human interleukin-2 mediated regression of established 3-day WP6 lung metastases. Thus, clone 8 re cognizes a biologically relevant tumor rejection antigen, making the V alpha 3/J alpha 27-V beta 8.2/D beta 2.1/J beta 2.4 TcR isolated from this clone useful as a probe for cloning the tumor-rejection antigen in the WP6 tumor as well as modeling, in mice, the TcR-based gene ther apies being developed for humans.