Influence of anti–TGF-β antibody and L-NMMA on the Mac1⁺-mediated suppressor activity. Suppressor assays (as in Figure 5) were performed in the presence of L-NMMA (100 μM), anti–TGF-β 140 pg/mL, or irrelevant control antibody (control chicken IgY, 140 μg/μL). (A) Influence of anti–TGF-β. (B) Influence of L-NMMA. Results are expressed as percent suppression of the proliferative activity that was detected in the absence of additional cell populations. Bars represent means ± SEs of 8 individual animals tested in 2 independent identically designed experiments. (^*P < .05 for comparison between groups, as tested by Kruskal-Wallis multiple comparison Z-test).