Figure 1.
Rapamycin has immunosuppressive activity independent of CD28 engagement. Lethally irradiated (1000 cGy) B10.BR recipients were given transplants of 15 × 106 T-cell–depleted marrow cells with or without 15 × 106 splenocytes from (A) CD28+/+ or (B) CD28-/- C57BL/6 donors. Recipients were treated intraperitoneally with rapamycin or with control solvent. Numbers of recipients are indicated in parentheses. Data were pooled from 3 (A) and 2 (B) experiments, respectively.