To evaluate the role of Blimp-1 on CD4-driven tumor control, we isolated CD4+ TILs from MCA205 tumors and dLNs from αCTLA-4-treated Prdm1fl/fl or Prdm1−/−Cd4cre mice and transferred them to MCA205-bearing Rag1−/− mice. The gene discussed is PRDM1; the disease is neoplasm.