Targeted protein degradation via CAR endocytosis of antigen in T cells

Targeted protein degradation (TPD) relies on molecules engaging host protein degradation machinery. Here, we developed a novel TPD platform based on antigen endocytosis and degradation by chimeric antigen receptor (CAR) T cells. T cells expressing a CAR with TNFR1 as the antigen-binding domain (TNFR1T) were able to bind, endocytose, and degrade TNF in vitro. To enhance in vivo expansion and persistence of TNFR1T cells, BCOR and ZC3H12A were depleted, generating TNFR1TIF cells. In a human TNF transgenic mouse model of rheumatoid arthritis, a single infusion of TNFR1TIF cells sustainably reduced serum hTNF to near wild-type levels, leading to long-term disease remission. This approach extends CAR T cell targets from cells to extracellular proteins, enabling long-term degradation of inflammatory cytokines and durable remission in chronic inflammatory diseases.