It has been reported that GITR ligation protects T cells from activation-induced cell death leading to an increase in memory cells.11,20,21 In agreement with this theory, we observed that Delta-24-GREAT treatment resulted in the development of a systemic immune response as demonstrated by resistance of long-term survivor mice to tumor rechallenge experiments accompanied by an increased CD8+ T central memory. This evidence concerns the gene CD8A and neoplasm.