FIG. 4.

Detection of Spy0843 (A) and Spy1972 (B) on the GAS cell surface by flow cytometry. Control antibody (unshaded histograms) and purified anti-Spy0843 and anti-Spy1972 (shaded histograms) were incubated with strain MGAS5005 (serotype M1) and analyzed by flow cytometry. The unshaded histograms represent the level of nonspecific binding of the control antibody to MGAS5005. The shaded histograms indicate increased fluorescence due to the binding of anti-Spy0843 or anti-Spy1972 antibody to the MGAS5005 cell surface.