FIGURE 4.

Chemokine induction of SPA release from MRSA does not require new protein synthesis. MRSA was incubated in the presence or absence of 500 nm CXCL9 and 16 mg/ml chloramphenicol (Cm) for the time indicated on the x axis at room temperature, then extracellular SPA concentration (A) and total SPA content (B) were determined by ELISA as described under “Experimental Procedures.” The experiment was performed using low bacterial density (A₆₀₀ = 0.1) to optimize the induced SPA signal. Data are from a single experiment representative of two experiments performed.