Figure 7.

Endogenous PGE₂ is necessary for inducible IL-33 expression and type 2 immunopathology in response to Alternaria. WT and mPGES-1 KO mice were treated with four intranasal doses of Alternaria (12 μg) over 9 days. On day 10, mice from the indicated groups were euthanized for the studies. A–C, total lung cell numbers (A), total lung eosinophils (B), and lung ILC2 numbers (C) in WT and mPGES-1 KO mice in PBS and Alternaria-challenged mice. D, qPCR quantification of the IL-33 mRNA transcript in lung single-cell suspensions in WT and mPGES-1 KO Alternaria-challenged mice (IL-33 transcripts were below detection levels in PBS-challenged mice). Data are presented as mean ± S.D. of at least three independent experiments. Statistical significance was determined using an unpaired t test. *, p < 0.05; **, p < 0.005; ***, p < 0.0005.