Enhanced protection by Th17 cells involves more potent qualitative and quantitative helper effects for the development of <i>T</i>. <i>cruzi</i>-specific CD8⁺ T cells.

<p>RAG KO mice were adoptively transferred with polyclonal CD8⁺ T cells and Th1 or Th17 cells and then infected systemically with <i>T</i>. <i>cruzi</i>. (A) Greater absolute numbers of CD8⁺ T cells were recovered from mice co-adoptively transferred with Th17 cells at 7 days post-infection. (B) The mean fluorescence intensity (MFI) of T-bet expression in these same CD8⁺ T cells was increased over mice receiving CD8⁺ T cells alone or CD8⁺ T cells with Th1 cells, as measured by ICS. (C) Co-culture of sub-optimally stimulated CD8⁺ T cells with activated Th17 cell SN <i>in vitro</i> also induced higher T-bet expression than co-culture with Th1 cell SN. (D-E) Antigen-specific total and CD8⁺ T cell responses were studied 7 days post-challenge by IFN-γ ELISPOT (D) and intracellular cytokine staining (E), respectively. Similar results were detected in multiple experiments.