FIGURE 5.

p4 reduces MRSA burden and accompanying skin inflammation in the experimental model of AD. Mice were subjected to tape-striping and OVA challenge to induce an AD-like phenotype (Atopy). (A) Allergic changes were monitored by ELISA specific for total or OVA-specific serum IgE levels, upper and lower panels, respectively. The negative control represents sera from sex- and aged-matched unchallenged mice (control). The positive control represents sera of mice immunized i.p. with OVA in the presence of alum adjuvant for 10 days (OVA+Alum). The antibody titers are shown as mean ± SD ng/ml or OD (optical density units) for the indicated sets of sera. n = 4–5, ***p < 0.001; **p < 0.01; *p < 0.05 by Kruskal–Wallis test with post hoc Dunn’s multiple comparisons test. (B) Mice were subjected to tape-striping and OVA challenge, followed by bacterial challenge and/or treatment with the indicated factors. Data points indicate the number of live bacteria recovered from the skin surface 24 h after application of S. aureus, n = 8. **p < 0.01; *p < 0.05 by the Kruskal–Wallis test with post hoc Dunn’s multiple comparison test. (C) Representative Gram staining of the indicated skin biopsies from the AD model. S. aureus on the skin surface is indicated by arrows. (D) Representative fluorescence microscope images of the indicated AD skin, stained with Hoechst to detect DNA (blue) and anti-CD45 to identify leukocytes (red). (E) Data points indicate # of leukocytes (CD45+) infiltrating the indicated area of AD skin, n = 3 mice per group. ****p < 0.0001; ***p < 0.001; ns, not significant; by one-way ANOVA with post hoc Dunnett’s multiple comparisons test. Scale bar = 20 μm.