We were particularly interested in NK cells because these cells have been shown to synergize with CD4+ T cells to reject tumors.24 However, our previous data suggested that depletion of NK cells with antibodies to NK1.1 had no affect on tumor immunity11 except for anecdotal evidence that mice acquired autoimmune vitiligo faster than animals that only received TRP-1 cells. This evidence concerns the gene CD4 and neoplasm.