Smith, B. E.; Draper, L. M.; Garmilla, A.; Perez, C. R.; Singh, N.; Padilla, L. T.; Xu, E. J. K.; Gaglione, S. A.; Shen, J.; Conce Alberto, W. D.; Zhao, Q. H.; Dobson, C. S.; Roybal, K. T.; Dougan, M.; Birnbaum, M. E.; Dougan, S. K.

Cancer immunotherapies rely on tumor-specific T cells, which arise endogenously in most patients with cancer, but can be low frequency and poorly functional. Methods to specifically identify, expand, and manipulate tumor-specific T cells at the rare frequencies found in peripheral blood would enable new immunotherapeutic strategies. Here, we demonstrate an approach to virally transduce polyclonal tumor-reactive T cells across any MHC haplotype and in the absence of knowing the cognate antigen. By generating lentiviral vectors that selectively transduce cells expressing 4-1BB (CD137), a marker of T cell activation, we can transduce antigen-specific T cells with user-defined genetic cargoes that can selectively expand and track individual clonotypes via single-cell sequencing. Anti-4-1BB lentiviruses (4-1BB LVs) encoding therapeutic cargoes can also enhance antigen-specific T cells to extend survival in a xenograft model of human melanoma and transduce tumor-infiltrating T cells from patients with ovarian cancer. Overall, the 4-1BB LV platform targets antigen-specific T cells in a manner agnostic to both the antigen and presenting MHC, with potential applications in adoptive cell therapy manufacturing and TCR identification.