CD4 and neoplasm: Examination of tumor-associated T cells showed that IL-2/CD40 reduced young, but not elderly, CD4+ T cell (Supplementary Figure S8A) and Treg proportions (Supplementary Figure S8A), leaving elevated Treg proportions in elderly IL-2/CD40-treated tumors (Supplementary Figure S8A), implying increased suppressive activity in elderly tumors.