Combined CLEC2d Expression and CD58 Loss Mitigate Rejection of Allogeneic T Cells

Immunogenicity of allogeneic chimeric antigen receptor (CAR) T cell therapies may preclude durable therapeutic responses and broad clinical implementation. Although genetic knockout (KO) of beta-2-microglobulin (B2M) is commonly employed to abrogate HLA class I expression thereby preventing allorecognition by recipient T cells, this deficiency induces missing-self responses by natural killer (NK) cells. Here, we demonstrated that forced expression of a chimeric membrane-bound CLEC2d, an inhibitory ligand of CD161, and concurrent loss of CD58 (LFA-3), an adhesion ligand of CD2, substantially mitigated NK cell responses against allogeneic B2MKO T cells. This combination reduced in vitro NK cell-dependent lysis to a greater extent than either strategy alone and increased the in vivo persistence of these cells after infusion into NK cell-replete humanized mice. Collectively, these findings demonstrate that the convergence of orthogonal genome engineering approaches effectively averts NK cell-driven rejection of allogeneic T cells for immunotherapy.