PRDM1 and neoplasm: Reduction in CD4+ T cell numbers and longevity in response to antigen presentation by a combination of B cells and dendritic cells, compared with dendritic cells alone, would be consistent with the findings of Candolfi et al., who used B cell-specific deletion of Prdm1 to show that B cell differentiation to antibody secretion was not required for their negative effect on T cell-dependent tumor control [32].