FIGURE 3.

Chemokine induction of SPA release from MRSA is dependent on bacterial density. Bacteria at the indicated density were incubated with or without 500 nm CXCL9 or CXCL10 (plus and minus signs, respectively) overnight at room temperature, and supernatants were then analyzed for SPA content by SDS-PAGE/Western blot using anti-protein A antibody (A, C). SPA content was quantified by NIH ImageJ software, and the ratio of SPA signal in the presence and absence of chemokine was plotted (B, D).