a) Flow cytometry analysis of T and B cells in the spleen and LN of naïve C57BL/6 mice, untreated C57BL/6 recipients of BALB/c cardiac allografts on day 7 post-transplant, CB-conditioned, tolerant allograft recipients on day 120 post-transplant, and CB-conditioned allograft recipients subjected to irradiation on day on day 120 post-transplant. b) Serum from naïve, untreated-rejecting allograft recipients on day 7 post-transplant, CB-conditioned, tolerant allograft recipients on day 120 post-transplant, and CB-conditioned allograft recipients subjected to irradiation on day on day 120 post-transplant was collected and tested for reactivity to BALB/c thymocytes using flow cytometry-based analyses to determine donor-reactive antibody titers. Data indicate mean titer ± SEM for n=5/group and are representative of two independent experiments. **p < 0.01