Abstract

Gliomas are brain tumors characterized by immunosuppression. Immunostimulatory agonistic CD40 antibodies (CD40) are in clinical development for solid tumors but are yet to be evaluated for glioma. Here, systemic delivery of CD40 led to cytotoxic T cell dysfunction and impaired the response to immune checkpoint inhibitors in preclinical glioma models. This was associated with an accumulation of suppressive CD11b+ B cells. However, CD40 also induced tertiary lymphoid structures (TLS). In human glioma, TLS correlated with increased T cell infiltration indicating enhanced immune responses. Our work unveils the pleiotropic effects of CD40 therapy in glioma, which is of high clinical relevance.