Inhibition of the Th2 response potentiates IL-17A and IL-17F production but is not sufficient to exacerbate neutrophil recruitment or AHR development.

Mice were exposed to 15ppm NO2 for 1 hour on day 1. All mice were exposed to OVA on days 1-3 and again during challenge on days 14-16 and analyzed 48 hours after the final antigen challenge. IgG isotype control antibody was administered one day prior to NO2 exposure and one day prior to OVA challenge. Anti IL-4 neutralizing antibody was administered one day prior to sensitization on day 0. A second group also received anti-IL-4 antibody one day prior to OVA challenge on day 13. Because we observed no differences in AHR, BAL cell counts, or cytokine production between mice that received anti-IL-4 at sensitization only on day 0 or on day 0 and day 13, we combined anti-IL-4 treated mice for statistical analysis. 48 hours following the final antigen challenge, lungs were removed and enzymatically digested. Single cell suspensions were restimulated in the presence of 200 μg/ml OVA antigen for 96 hours prior to the harvesting of cell supernatants and analysis of cytokine production. IL-17A (A) and IL-17F (B) were quantitated by Milliplex. IL-5 (B) and IL-13 (C) were quantified by ELISA. BAL total cells (E), Macs (F), PMNs (G), and Eos (H) were determined. Percent baseline and average percent baseline per dose of methacholine were calculated for R (I-J) and E (K-L). Statistics were performed by student’s t-test (A-D), 2-way ANOVA (J and L) or 1-way ANOVA (E-H) and Tukey post hoc analysis. **** p < 0.0001, *** p < 0.001, ** p < 0.01, * p < 0.05 compared to non-inflamed unless otherwise indicated by brackets. ND, not significantly different compared to non-inflamed. n = 6-12 per group.