FIG. 4.

Two-dimensional Western blot analysis of stationary-phase GAS culture supernatant proteins with human and mouse sera. Concentrated culture supernatant proteins (60 μg) obtained from the speB mutant of MGAS 5005 (serotype M1) were separated in the first dimension by isoelectric focusing (pH 3 to 10) and in the second dimension by SDS-PAGE with 10% gels. (A) Convalescent-phase serum (diluted 1:20,000) obtained from a human with GAS pharyngitis; (B) serum obtained from a patient with acute rheumatic fever; (C) convalescent-phase serum (diluted 1:20,000) obtained from a human with streptococcal toxic shock syndrome caused by an M1 GAS strain. Control sera obtained from these patients were essentially unreactive when used at the same dilutions. The numbered and lettered triangles indicate the proteins reactive in the Western blots that correspond to the protein spots (numbered identically) in Fig. 1.