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. 2003 Dec;71(12):7119–7128. doi: 10.1128/IAI.71.12.7119-7128.2003

FIG. 9.

FIG. 9.

Immunofluorescence microscopy of FHL-1-Fba-mediated invasion. A549 cells were infected with GAS strain 90-226 emm1::km in the presence of FHL-1. After incubation, cells were fixed, blocked, and incubated with rabbit anti-Fba serum, followed by incubation with donkey anti-rabbit IgG labeled with rhodamine red. After removal of unbound antibodies, cells were permeabilized with Triton X-100 and incubated successively with anti-Fba serum and goat anti-rabbit IgG labeled with FITC. Specimens were examined by fluorescence microscopy for intracellular (FITC-labeled) and extracellular (FITC- and rhodamine red-labeled) GAS. (A) Phase-contrast microscopy of infected A549 cells. (B) The same field as that shown in the other panels, irradiated for visualization of extracellular GAS. (C) The same field viewed for the presence of intracellular and extracellular GAS. Arrows in panels A and C indicate intracellular streptococci.