GGA and HSF1A increased IL-17A–producing cells within CD4⁺splenocytes from mut-Stat3 mice. Representative flow cytometry analysis (A) of TCR⁺ CD4⁺ T cells in splenocytes from mut-Stat3 or WT mice; IL-17A intracellular staining was performed upon isolation without PMA/Ionomycin stimulation (Unstimulated) or after incubation in Th17 polarizing conditions either without proteostasis modulators (no PMs) or with GGA (3 μM) or HSF1A (3 μM) and stimulation with PMA/Ionomycin. (B) The percentage of IL-17A–producing TCR⁺CD4⁺ cells measured in the presence of GGA or HSF1A was normalized to the percentage in the absence of proteostasis modulators and the mean and SD (vertical bars) plotted for each mouse in both the mut-Stat3 and WT groups (n = 4; P values determined using paired Student t test are shown).