CD4 and neoplasm: Intracellular staining detection showed that, after stimulation with B16-F10 tumor cells in vitro, the percentage of IFN-γ+ CD4+ T cells and IFN-γ+ CD8+ T cells from mice vaccinated with B16-F10-derived Ub-enriched proteins was higher than that from mice that vaccinated with tumor cell lysate, Ub-depleted proteins or PBS (Figure 3E).