FIG 5.

EseB antibody blocks E. tarda autoaggregation and biofilm formation. E. tarda wild-type cells cultured in DMEM in tubes or 24-well plates were supplemented (Treated) with EseB antibody at 1:2,000, 1:1,000, 1:200, 1:100, and 1:50 dilutions. Naive mouse serum was added to E. tarda wild-type cultures at a 1:50 dilution and is labeled Untreated. (A) EseB antibody added at 15 hps inhibits autoaggregation of E. tarda cultured in DMEM in a dose-dependent manner, as shown by OD₅₄₀ values of the culture supernatants and images of autoaggregation in glass tubes. *** , P < 0.001; **, P < 0.01. (B) Biofilm formation by E. tarda cultured in DMEM is inversely proportional to the amount of EseB antibody added at 15 hps. Crystal violet staining and quantification of dissolved crystal violet were performed to evaluate the biofilm formation ability in the presence of EseB antibody. ***, P < 0.001. (C) Confocal laser scanning microscopy images of top-down views and orthogonal views of filament formation when EseB antibody was added at 15 hps. There were fewer EseB filaments with increasing concentrations of EseB antibody. The amounts of EseB antibody added are indicated for dilutions of no less than 1:100. (D) Mature biofilm formed by E. tarda is not influenced by EseB antibody added at 24 hps. The biofilms were examined by crystal violet staining at 4 h post-EseB antibody supplementation. The quality and amount of biofilm formation were revealed by crystal violet staining. ***, P < 0.001.