CD4 and neoplasm: Prophylactic transfer of Rnf5−/− microbiota was sufficient to delay tumor growth (Fig. 4a), as well as to enhance infiltration of tumor-specific CD45+, CD4+, CD8+ T cells and increase cytokine production (Fig. 4b), supporting a role for the Rnf5−/− microbiota in mediating antitumor effects.