We recently demonstrated a cell-autonomous role for FcγRIIB in regulating graft-specific CD8+ T cell responses in the context of transplantation, and during the course of those studies, we discovered that adoptive transfer of Fcgr2b–/– OT-I T cells into recipients of B16-OVA melanoma tumors resulted in an approximately 40% reduction in tumor volume by day 14 (24). The gene discussed is CD8A; the disease is melanoma.