CD4 T cell responses are enhanced by IL-10R blockade and vaccination. (A) LCMV-Cl 13–infected mice were treated and analyzed as described in Fig. 1. The frequency of cytokine-producing, LCMV-GP61-80–specific CD4 T cells was quantified by ex vivo peptide stimulation and intracellular staining. Flow plots are gated on CD4 T cells and illustrate the frequency of IFNγ- and IL-2–producing, LCMV-GP61-80–specific CD4 T cells after each treatment (39 d after infection). Data are representative of 4–5 mice per group. (B) The graph illustrates the number of IFNγ-producing, LCMV-GP61-80–specific CD4 T cells (quantified as described in Fig. 1 C). *, P < 0.05 compared with untreated and DNA vaccination alone. **, P < 0.05 compared with all other treatment groups. (C) The bar graph illustrates the mean fold increase in the number of IL-2–producing, LCMV-GP61-80–specific CD4 T cells after each treatment regimen compared with isotype treatment. Individual bars represent the mean value ± the SD of 3 experiments containing for 4–6 mice per group. *, P < 0.05 compared with untreated and DNA vaccination alone. **, P < 0.05 compared with all other treatment groups.
