N-glycosylation engineering in chimeric antigen receptor T cells enhances anti-tumor activity

Abstract

Recently, chimeric antigen receptor (CAR) T cell technology has revolutionized cancer immunotherapy. This strategy uses synthetic CARs to redirect T cells to specific antigens expressed on the surface of tumor cells. Despite impressive progress in the treatment of hematological malignancies with CAR T cells, scientific challenges still remain for use of CAR T cell therapy to treat solid tumors. This is mainly due to the hostile tumor microenvironment and CAR-related toxicities. As the glycans decorating the T cell surface are implicated in T cell activation, differentiation, proliferation, and in the interaction of human T cells with tumor cells, we studied the role of human T cell glycosylation in more depth by manipulating their glycome. In this context, there is in vitro evidence that beta-galactoside binding lectins (Galectins) can have a strong impact on the functionality of tumor-infiltrating T cells. The high-affinity poly-LacNAc N-linked galectin ligands are mainly synthesized onto the beta1,6-GlcNAc branch introduced by N-acetylglucosaminyltransferase V (GnTV, encoded by Mgat5). We showed that knocking out Mgat5 in CD70 targeting CAR T cells leads to lower densities of poly-LacNAc modifications on the CAR T cell surface. Most interestingly, our results indicate that MGAT5 KO CD70 CAR T cells show enhanced potency to control primary tumors and relapses.