CD80 and neoplasm: Despite Gl261 tumors being noted as partially immunogenic, expressing MHC I but low levels of MHC II, B7-1 and B7-2 [35], we saw no significant differences in ‘anti-tumor’ Th, Tc, NK and NK/T immune cell populations infiltrating the tumor microenvironment over time, although a correlation with decreasing plasma cytokines was noted at day 14 post-inoculation.