Human antigen-specific invariant NKT cells generated by the TIL 1383I T cell receptor gene transfer (P2098)

Abstract

Abstract Human invariant NKT cells (iNKT cells) are a novel lymphocyte population characterized by an invariant T-cell receptor (Vα24/Vβ11). iNKT cells activated with αGalCer and IL-2 have been shown to produce large amounts of cytokines such as IFN-γ and also have potent killing activity against various tumor cell lines. One major hurdle to studying the anti-tumor activity of iNKT cells is they don’t recognize antigens presented by classical MHC molecules and their tumor antigen specificity is unknown. Therefore, we expressed the MHC class I restricted TIL 1383I TCR into iNKT cells to better study their biology and anti-tumor activity. The 1383I TCR is a high affinity TCR that recognizes the melanoma antigen tyrosinase presented by HLA-A2. In this study, we report the production and function of the TIL 1383I TCR transduced human iNKT cells. iNKT cells were activated and expanded from normal PBMCs by stimulating them with αGalCer in the presence of IL-2 and IL-15. The iNKT cells were isolated using iNKT magnetic beads and transduced using retroviral vectors encoding the TIL 1383I TCR. The TIL 1383I TCR transduced iNKT expression was measured by flow cytometry (FACS) and their anti-tumor activity by intracellular cytokine staining. The TIL 1383I TCR transduced iNKT cells specifically produced IFN-γ in response to tyrosinase peptide loaded T2 cells and HLA-A2+/tyrosinase+ human melanomas. These results indicate that iNKT cells can be engineered to recognize normal tumor antigens.