T1- and T2-mediated GVHD effects. (A) Histologic GVHD score. Liver, small intestine, and stomach (day 28 after BMT) were scored for GVHD (range, 0-4). The score from each organ was combined for each recipient, and these total scores were averaged (n = 3; maximum GVHD score, 12). (B) T1 and T2 infiltration of liver. Allogeneic T1 and T2 populations were generated from Ly5.1 B6 donors. On days 5 and 14 after BMT, recipient livers were harvested, and the single-cell suspensions were evaluated by flow cytometry for the presence of CD45.1⁺ T1 or T2 cells. The percentage of CD45.1+ T cells was determined for each recipient (n = 3) in the treatment cohort with data represented as mean ± SEM.