The effect of cell dose on engraftment of B6.SJL marrow cells into 100-cGy–irradiated BALB/c mice subjected to spleen cell pre-exposure and CD40 ligand blockade.

BALB/c hosts irradiated with 100 cGy were infused with varying levels of B6.SJL marrow cells after splenic presensitization (day −10, 10 million cells) and CD40 ligand antibody blockade (days −10, −7, −3, 0, and +3). Results are expressed as percentage (%) engraftment (CD45.1⁺ cells) ± 1 SEM from 3 to 15 weeks after transplantation. There were 5 mice per group. There was a significant trend toward increasing engraftment as the cell doses increased; for weeks 3, 6, 9, 12, and 15 weeks P values were .01, .02, .12, .03, and .03, respectively, although when analyzed independently with Wilcoxon rank order there was no significant difference between the 80 and 120 million cell groups.