CD4 and neoplasm: To elucidate the relative contribution of various immune cell subsets to the anti-tumor activity demonstrated following mCD38-mAtt treatment, NK cells, CD8 T cells, or CD4 T cells were selectively depleted in A20 or CT26 tumor-bearing mice using depleting αAsialo GM-1 (for NK cell depletion), αCD8, or αCD4 antibodies, respectively, prior to treatment with mCD38-mAtt (Fig 5).