Microenvironment and Immunology T Lymphocytes Expressing a CD16 Signaling Receptor Exert Antibody-Dependent Cancer Cell Killing

To expand applications for T-cell–based immunotherapy in cancer, we designed a receptor that binds the Fc portion of human immunoglobulins and delivers activation signals. The construct included the high-affinity CD16 (FCGR3A) V158 variant, CD8a hinge, and transmembrane domains, alongwith signaling domains fromCD3z and 4-1BB (TNFRSF9), forming a chimeric receptor termed CD16V-BB-z. After retrovirus-mediated expression in human T cells, CD16V-BB-z bound humanized antibodies with higher affinity than a control receptor containing the more common F158 variant. Engagement of CD16V-BB-z provoked T-cell activation, exocytosis of lytic granules, and sustained proliferation, with amean cell recovery after 4-week coculturewithDaudi lymphoma cells and rituximab of nearly 70-fold relative to input cells. In contrast, unbound antibody alone produced no effect. CD16V-BB-z T cells specifically killed lymphoma cells and primary chronic lymphocytic leukemia cells in combinationwith rituximab at a low effector:target ratio, evenwhen assayed onmesenchymal cells. Trastuzumab triggered CD16V-BB-z–mediated killing of HER2 (ERBB2)þ breast and gastric cancer cells; similar results were obtainedwith an anti-GD2 antibody in neuroblastoma and osteosarcoma cells. Furthermore, coadministration of CD16V-BB-z T cells with immunotherapeutic antibodies exerted considerable antitumor activity in vivo. Signaling mediated by 4-1BB-CD3z induced higher T-cell activation, proliferation, and cytotoxicity than CD3z or FceRIg, and the receptor was expressed effectively after mRNA electroporation without viral vectors, facilitating clinical translation. Our results offer preclinical proof of concept for CD16V-BB-z as a universal, next-generation chimeric receptor with the potential to augment the efficacy of antibody therapies for cancer. Cancer Res; 74(1); 93–103. 2013 AACR