Immunosuppression associated with cGvHD responsible for the deficit antiviral T-cell responses. Allogeneic transplant recipient with cGvHD, syngenic transplant with no GvHD, and normal C57BL/6 mice were intraperitoneally vaccinated with 1 × 10⁶ CFUs Lm-MCMV. Lymphocytes were harvested from the blood, liver, and spleen collected on days 0 and 7 after vaccination, and MCMV peptide–specific tetramer-positive CD8⁺ T cells were measured by FACS analysis. (A) Representative dot plots of donor spleen–derived tetramer-positive CD8⁺ T cells in the blood, liver, and spleen of recipients with cGvHD and no GvHD and CD3⁺-gated populations of normal C57BL/6 mice. (B) Absolute number of tetramer-positive CD8⁺ T cells per organ measured from the recipients with cGvHD, no GvHD, and normal C57BL/6 mice. *P < .05 in blood and liver and *P < .001 in spleen (Student t test) are for the decreased absolute numbers of MCMV peptide–specific tetramer-positive CD8⁺ T cells per organ in recipients with cGvHD compared with without GvHD or normal mice. Three to 5 mice were used per group in each time point.