Anti-cotinine CAR-modified T cells provides a novel switchable CAR platform using cotinine-conjugated adaptor molecules

Abstract

Abstract T cells engineered with chimeric antigen receptor (CAR T cells) have been reported to provide potent anti-tumor effects in various preclinical experimental settings. Subsequently, CAR T cells against some hematologic malignancies showed favorable results in early clinical trials. However, there are various obstacles to overcome in generalizing this CAR T platform. Usually CAR T cells can target only a single tumor antigen although generation of CAR T cells takes considerable labor and expenses. Also, excessive activation of CAR T cells often leads to adverse side effects that need to be controlled. Switchable CAR T platforms using anti-hapten CAR T cells and hapten-conjugated adaptor antibodies was proposed as a novel way to target multiple antigens using single CAR T cells. Also, removal of hapten-conjugated adaptor antibodies can limit adverse side effect caused by CAR T cell recognition of the antigen. Here, we report a novel switchable CAR T platform using a chemical hapten, cotinine. Anti-cotinine CAR T cells generated using anti-cotinine single chain Fv recognized cotinine-conjugated adaptor molecules such as aptamers and antibodies. Especially, anti-cotinine CAR T cells complexed with cotinine-conjugated antibodies could recognize tumor antigens on the surface of tumor cells, which led to activation of CAR T cells and resulting cytotoxicity on tumor cells. Thus, we propose that anti-cotinine CAR T platform may provide useful tools for a novel multi-targeting CAR T therapy.