CD8⁺ T cells are not required for 3H3-mediated inhibition of autoantibody production. CD4⁺ and CD8⁺ T cells were depleted in vivo with 200 μg anti-CD4 mAb and 300 μg anti-CD8 mAb, respectively, on days -2, 0, and 2. Donor CD4⁺ T cells or CD8⁺ T cells were depleted before transfer as described in “Materials and methods.” Two weeks after disease induction, anti-DNA IgG₁ levels were measured. Neither donor nor total (host plus donor) CD8⁺ T cells influenced the effect of 3H3 (A), whereas depletion of either donor or total (host plus donor) CD4⁺ T cells prevented the development of cGVHD in both groups (B). OD values are shown as means ± SD of n = 5 per group at 10-fold dilution of samples, and are representative of 2 experiments. ^*P < .05 between the control Ig–treated group with no depletion and the indicated group.