(L) 6-8 weeks old C57BL/6 mice were injected with MC38 cells. When tumors reached ~150-200mm3, animals were intraperitoneally (i.p.) injected with 50μg of indicated antibody every third day. On day 18, tumors were harvested, sized matched and pooled by treatment group, exposed to collagenase/DNase and were single cell suspensions enriched for CD8+ cells. Enriched CD8+ T-cells from various treatments were restimulated with anti-CD3 (OKT3) antibody for 4 additional hours. CD8 gated cells were next analyzed for IFN-γ intracellular expression using flow cytometry. 