IL-17A secretion increases in response to decreasing wild type peptide concentrations. Target cells, pulsed with increasing concentrations of wild type gp100 peptide, were incubated at a 1:1 ratio with peripheral blood mononuclear cells transduced with one of the SILv44, T4H2 or R6C12 TCRs. At concentrations lower than 5 nM gp100209–217 peptide, (A) IFN-γ concentrations are gradually outperformed by (B) IL-17A secretion, revealing a lower optimum peptide concentration for the inflammatory cytokine.