Fig. 4.
The effects of poly(I:C) pretreatment and ST2 blockade on local and systemic responses during i.n. S. aureus enterotoxin-induced lung injury. C57BL/6 mice were i.p. injected with PBS or 200 μg poly(I:C) on day –3 followed by i.n. inoculation with 1 μg SEA on day 0. Responses were analyzed 2 d post SEA challenge. To block ST2 signaling, two doses of 500 μg anti-ST2 antibody were i.p. injected at −24 h and +6 h, respectively, in relation to SEA challenge. (A) Cytokines in the BAL fluid and influx of Gr-1hi cells. (B) Immunohistochemical staining of IL-33 in paraffin-embedded lung sections (20× magnification). (C) BAL fluid IL-5 level in C57BL/6 versus IL-33−/− mice. (D) Splenocytes were restimulated with SEA ex vivo, and the frequency of effector CD8 T cells was analyzed. (E) Enumeration of ST2+ effector cells in the spleens. Data shown were obtained from at least three independent experiments.