Anti-CD2 + 48 MoAb infusion slows the recovery of lymphohematopoiesis in the BM and splenic compartments in lethally irradiated recipients of congenic BM grafts. B6 recipients were lethally irradiated on day −1 and then administered 3.0 × 10⁶ BM from B6-CD45.2 congenic donors on day 0. Mice were treated with irrelevant IgG or CD2 + 48 MoAb as described in Fig1. At the indicated time periods listed on the x-axis, three mice per group were analyzed for reconstitution of the BM compartment as shown in Table 4. The absolute number of cells is listed on the y-axis. Data, mean values ± 1 standard deviation of the mean, are depicted. Comparisons between the groups which were significant (*P < .05; **P < .01) are shown. Representative histograms from these mice are shown in Fig 3A. These data were replicated in a second experiment as shown in Table 7.