C57BL/6 skin allograft survival in BALB/c recipients of C57BL/6 bone marrow.

Both chimeric and nonchimeric BALB/c mice from among those described in Table 1 were selected at random and transplanted with a C57BL/6 skin graft 7 to 19 weeks after bone marrow transplantation as described in “Materials and Methods.” For purposes of analysis, mice were divided into 4 groups. Mice in group 1 had received 400 or 500 rad of conditioning radiation plus anti-CD154 mAb and were chimeric. MST of grafts in this group was more than 166 days. Mice in group 2 had received 500 rad of conditioning radiation but no anti-CD154 mAb and were chimeric. MST of grafts in this group was 9 days. Mice in group 3 had received 400 or 500 rad of radiation plus anti-CD154 mAb but were not chimeric. Mice in group 4 were given 400 rad of radiation but no anti-CD154 mAb and were not chimeric. MST of grafts in both group 3 and group 4 was 9 days. Graft survival in group 1 was significantly longer than in any other group (P<.0001). Censored data—mice that died or were killed for histologic study or were still alive at the end of the experiment—are indicated by vertical lines.