Figure 1. Tc17 cells are induced and recalled in the absence of CD4⁺ T cells.

Mice were vaccinated as described in Methods. CD4⁺ T cells were depleted using GK1.5 mAb i.v. weekly throughout the experiment. A. Percent CD8⁺ T cells producing IL-17 in draining LNs (dLNs) and spleen at 19 days post-vaccination in the presence (left panels) or absence (right) of CD4⁺ T cells as assessed by flow cytometry. B. In the left two panels, OT-I T cells (1×10⁶) were transferred to naïve congenic CD4^−/− mice and vaccinated with recombinant Blastomyces expressing the OT-I epitope SIINFEKL. At day 14, dLNs and spleens were harvested and stimulated ex vivo with OVA peptide. In the right three panels, dLNs were harvested and cultured with BMDCs in the presence or absence of heat-killed yeast. Yeast-specific OT-I and endogenous Tc17 cells were enumerated by flow cytometry. The percent (C) or number (D) of polyclonal and yeast-specific Tc17 cells during recall response in the lung 3–4 days after pulmonary infection with wild type virulent Blastomyces. Values are mean ± SD of 4 mice/group. * p<0.05 vs. unvaccinated mice; and ^† p<0.05 vs. vaccinated CD4⁺ T-cell sufficient mice.