Figure 5

CD40L and cytokines in regulation of the helper activity of CD57⁺ GC-Th cells. (A and B) Effects of endogenous CD40L and cytokines on the helper activity of CD57⁺ GC-Th cells were determined. In cultures of CD57⁺ GC-Th cells with naïve or GC-B cells, neutralizing antibodies to IL-4, IL-10, IFN-γ or CD40L or control antibodies (mouse IgG1) were added. *Significant differences from the control group (control antibody). (C and D) Effects of exogenously added cytokines on the helper activity of CD57⁺ GC-Th cells were determined. To cultures of CD57⁺ GC-Th cells with naïve or GC-B cells, IL-4, IL-10, IFN-γ and TGF-β1 were added separately. Cells were cultured for 7 days followed by ELISA for IgM, IgG, IgA and IgE. Relative Ig secretion levels (the medium control = 1) obtained from 9 independent experiments were combined, and averages and standard errors are shown. *Significant differences from the control group (medium).