Effects of anti-CD45 treatment on syngeneic and allogeneic hematopoietic stem cell engraftment.
Mice were prepared for transplantation with the indicated conditioning regimens and received intravenous infusion with 2 doses of 2 × 107 total bone marrow cells on days 3 and 4 after anti-CD45 treatment. The number of mice per group is shown above each column. The results are reported as mean (± SD) percentage chimerism as determined by flow cytometry on day 30 after transplantation. In the syngeneic model (A), anti-CD45 treatment alone did not allow engraftment and lacked a significant additional effect in combination with 5.5 Gy TBI alone (P = .295 by unpaired 2-tailedt test). In the allogeneic model (B), anti-CD45 treatment permitted high-level chimerism when used in conjunction with 8 Gy TBI. The chimerism induced by conditioning with the CD45 plus 8-Gy TBI combination was superior to the results obtained with either anti-CD45 or TBI alone (P < .002 by unpaired 2-tailed ttest). Neither anti-GM1 alone nor coinjection of anti-CD45 and antibodies against CD4 or CD8 induced measurable chimerism. ns indicates not significant.
