Western blot analysis comparing the levels of FPI proteins between LVS and the ΔpdpC mutant. Whole-cell lysates of Francisella were separated on SDS-PAGE and FPI protein-specific antibodies were used to detect the levels of proteins in the two samples. An antibody against FupA was used as a loading control. Asterisks indicate unspecific bands. The assay was repeated at least three times.