CD4 and neoplasm: We have previously demonstrated RT can provide this additional immune activation to CpG + OX40 in ~ 100–150 mm3 B78 tumors by increasing IFN gene expression in the TME, increasing OX40 expression on tumor infiltrating CD4 + T cells, and increasing IFN-γ expression in CD8 + and CD4 + T cells in the tumor draining lymph node (TDLN) and spleen [25].