Elongation factor Tu is localized on external side of F. tularensis LVS membranes. Part A. Fluorescence microscopy analysis of LVS pellet incubated either with NIS (from rabbit or from mice), anti-EF-Tu or anti-LVS Abs all diluted 1/10,000. Bright fields (part A1) or fluorescence microscopy (part A2) of 15 fields for each group were observed at 63× magnification. Images are representative of 3 different experiments. Part B. Electron micrographs showing attachment of gold spheres to surface of LVS incubated either with anti-EF-Tu or rabbit anti-LVS Abs and examined by nc-IEM. Control micrograph of LVS incubated with murine NIS shows no beads on bacteria cell surface. Electron microscopy was observed at 20,000× magnification. Size bars equal 500 nm.