Figure 2.

The role of Hla and Panton–Valentine leukocidin (PVL) in tissue toxicity and disruption of skin integrity. Human skin explants were treated with 1 and 5 µg of α-toxin or PVL and a cocktail of both toxins at 1 µg each. (A) Lactate dehydrogenase (LDH) released from human skin during 24–72 h of treatment with staphylococcal toxins. Data are combined results from three independent experiments Each bar represents the mean ± SD, N ≥ 2 for each experiment. Where N ≥ 2 represents intra-experimental replicates. (B) Immunofluorescence image of human skin section showing the expression of ADAM10 within the layers the epidermis. Scale bar 50 µm. (C) Hematoxylin and eosin staining of skin cryosections taken 24 h post toxin treatment. White box represents a magnified area of the image. Scale bar is 100 µm. (D) Cryosections of human skin explant showing TUNEL-positive cells (in green) after 24 h treatment with Hla or PVL. Scale bar 50 µm. (E) Immunofluorescence images of E-cadherin signal on skin cryosections 24 h post toxin stimulation. Scale bar 50 µm. (F) LDH released from human skin during 24 and 72 h of treatment with a cocktail of Hla and PVL at 1 µg each. Each bar represents the mean ± SD (N = 3). Statistical analysis was performed by two-way ANOVA, with Tukey’s multiple comparison tests, **p ≤ 0.001, ***p ≤ 0.0002, and ****p < 0.0001. Asterisks on bars are a comparison between the treated and untreated skin while lines across bars are comparison between groups. White dotted lines in images represent the boundary between epidermis and dermis.