FIGURE 3.

Tfr cells directly suppress Tfh cell proliferation in vitro. nvB cells and primed Tfh cells were cultured in the presence (blue) or absence (red) of primed Tfr and stimulated with (A,B) anti-CD3 alone or (C,D) anti-CD3/anti-IgM for 3 d. Tfh cells were labeled with eF450 cell tracker according to manufacturer instructions prior to culture and assay for suppression of proliferation. CD19⁺ B cells were analyzed for GL7 expression, statistics were calculated and shown on the right. Statistical results are from five independent experiments showing SEM (n = 5). **p < 0.005, ***p < 0.0001, unpaired Student t-test.