Figure 1.

Fixed Francisella tularensis (Ft) LVS used herein for immunization studies retain the protein composition of their unfixed counter parts. Ten micrograms of live and fixed Ft LVS previously grown in Mueller Hinton Broth and Brain-Heart Infusion (BHI) were resolved by sodium dodecyl sulfate polyacrylamide gel electrophoresis and stained with Coomassie blue (A) or transferred for western blot analysis (B). Asterisks in A mark bands, which are visibly more abundant in the western blot of BHI-grown Ft (B). The membrane was probed with a cocktail of monoclonal antibodies specific for IglB, IglC, and a FopA-specific polyclonal mouse serum. IglB and IglC have previously been shown to be more abundant in BHI-grown Ft (7, 9). FopA is used here as a loading control. The ~18-kDa band visible under IglC is an unidentified, endogenously biotinylated Ft protein (likely AccB) detected by the streptavidin–horseradish peroxidase conjugate used during development of the western blots.