B6-into-BALB/c BMT was performed (850 cGy host irradiation). Cohorts received donor marrow alone ("BMT"); marrow and host-type TS/A tumor cells ("TSA"); or marrow, tumor cells, and additional donor T cells ("GVHD"). Other cohorts received marrow, tumor cells, donor T cells, and additional donor CD4+ Th2 cells generated ex vivo in high-dose rapamycin (10 µM; administered on day 14 post-BMT); Th2 cells were generated from either wild-type donors (“Th2”) or IL-4 deficient donors (“Th2 4−/−”) or IL-10 deficient donors (“Th2 10−/−”). On day 19 post-BMT, lungs from treatment cohorts were removed to evaluate tumor burden; liver, stomach, small intestine, large intestine, cecum, and skin were harvested to assess GVHD. (a) For GVHD, each organ was scored on a scale of 0 to 4, with cumulative GVHD severity score shown (maximum value, 24). (b) For tumor burden, a semi-quantitative determination of tumor cell infiltration was scored on a scale of 0 to 4. n = 7 subjects were evaluated in each cohort.