CD4 and colitis: Importantly, cells of the myeloid lineage, and not T cells, were the primary source of inflammatory cytokines in this acute colitis model (Fig 3D), and depletion of CD4+ cells by antibody (starting at day 4 post DSS treatment) failed to alter acute DSS disease outcome in the various groups (Fig 3E), consistent with the hypothesis that Foxp3+CD4+ Tregs were not associated with disease outcome.