FIG 6.

Normal mouse serum proteins do not opsonize smooth B. abortus. (A) Coomassie blue-stained 10% SDS-PAGE gel of mouse (M) and human (H) proteins (10 μg/well) eluted from the surface of B. abortus 2308 or the Δper mutant after incubation of the respective serum with viable bacterial cells. Individual lines, corresponding to the different eluted fractions, were cut out and separated from the main gel as indicated in the figure; then each gel line was horizontally sliced (about 2-mm slices, from top to bottom), and the identities of proteins in each slice were determined by proteomic analysis. (B) Western blotting of mouse proteins (10 μg/well) eluted from the surface of B. abortus 2308 or the Δper mutant after incubation of the respective serum with viable bacterial cells. Western blots were developed with monoclonal antibodies against mouse C′3 or monospecific rabbit IgG anti-fibronectin.