Comparison of OX40-OX40L interactions with and CD8⁺T-cell–mediated GVHD lethality.

OX40-OX40L interactions are more potent regulators of CD4⁺as compared with CD8⁺ T-cell–mediated GVHD lethality. (A) Sublethally irradiated bm1 recipients (n = 8 per group) were given highly purified CD8⁺ T cells (0.3 × 10⁶) from OX40^+/+ (▴) or OX40^−/− (▵) donors as indicated. (B) Sublethally irradiated bm12 recipients (n = 8 per group per experiment) were given highly purified CD4⁺ T cells (0.3 × 10⁵) from B6 OX40^+/+ (▴) or OX40^−/− (▵) donors as indicated. Data from 2 replicate experiments with similar results were pooled. (C) Sublethally irradiated bm12 recipients (n = 8 per group per experiment) were given highly purified B6 CD4⁺ T cells (0.3 or 1 × 10⁵ as indicated in parentheses). Mice also were given either irrelevant (▴ or ■) or anti-OX40L (▵) mAb. (D) Lethally irradiated bm12 recipients (n = 5 per group) were given highly purified B6 CD4⁺ T cells (0.3 × 10⁶). Mice also were given either irrelevant or anti-OX40 mAb.