Figure 4

CD11b⁺ B1 cell suppression of naive CD4⁺T-cell activation is dependent on IL-10. (A, B) Sort-purified CD11b⁺ B1 cells were cocultured 1:1 with negatively selected naive CD4⁺ T cells plus plate-bound anti-CD3 in the presence of neutralizing anti-IL-10 antibody (N-ab) or isotype-control antibody (IC). Control cultures contained T cells with anti-CD28 in addition to anti-CD3 but no B cells (+). The fraction of CD4⁺ T cells expressing TNF-α after 3 d culture is shown for a representative experiment in (A) and for three independent experiments in (B). Vertical bars in (B) represent mean values and lines indicate SEM.