Dual T cell receptor/chimeric antigen receptor engineered NK‐92 cells targeting the HPV16 E6 oncoprotein and the tumor‐associated antigen L1CAM exhibit enhanced cytotoxicity and specificity against tumor cells

Abstract

AbstractThe human papillomavirus type 16 (HPV16) causes a large fraction of genital and oropharyngeal carcinomas. To maintain the transformed state, the tumor cells must continuously synthesize the E6 and E7 viral oncoproteins, which makes them tumor‐specific antigens. Indeed, specific T cell responses against them have been well documented and CD8+ T cells engineered to express T cell receptors (TCRs) that recognize epitopes of E6 or E7 have been tested in clinical studies with promising results, yet with limited clinical success. Using CD8+ T cells from peripheral blood of healthy donors, we have identified two novel TCRs reactive to an unexplored E618‐26 epitope. These TCRs showed limited standalone cytotoxicity against E618‐26‐HLA‐A*02:01‐presenting tumor cells. However, a single‐signaling domain chimeric antigen receptor (ssdCAR) targeting L1CAM, a cell adhesion protein frequently overexpressed in HPV16‐induced cancer, prompted a synergistic effect that significantly enhanced the cytotoxic capacity of NK‐92/CD3/CD8 cells armored with both TCR and ssdCAR when both receptors simultaneously engaged their respective targets, as shown by live microscopy of 2‐D and 3‐D co‐cultures. Thus, virus‐specific TCRs from the CD8+ T cell repertoire of healthy donors can be combined with a suitable ssdCAR to enhance the cytotoxic capacity of the effector cells and, indirectly, their specificity.