Figure 3.

Pathways involved in complement activation induced by Keratinocytes with persistent intracellular Staphylococcus aureus. (A) Infected keratinocytes were incubated with depleted or deficient sera along with respective reconstitution proteins as a source of complement, then stained for component 4 (C4) and terminal complement complex (TCC). Immunofluorescence (IF) representative images are shown in the left panel along with quantification on the right. (B) IF of C3 was quantified in different depleted and reconstituted sera to confirm participation of the alternative pathway. (C) IF of IgG was quantified using anti human IgG antibodies, binding of IgG was found to be increased in infected keratinocytes incubated with normal human serum (NHS) or HIS. Treatment of NHS with IdeS significantly decreased IgG binding. (D) IF C4 and TCC were quantified in infected keratinocytes incubated with NHS or IdeS treated NHS.