FIG 4.

Psl limits accessibility of OprF for antibody binding. (A) Mid-log-phase wild-type PAO1, Δpsl mutant, and Psl-overproducing (PAO1 Psl⁺⁺) P. aeruginosa strains were incubated with anti-OprF antibody conjugated with Alexa Fluor 488, and binding of OprF on the bacterial surface was determined by flow cytometry. (B) Cell extracts were blotted on a nitrocellulose membrane, probed with anti-Psl antiserum, and detected by chemiluminescence using an HRP-conjugated secondary antibody. **, P ≤ 0.005; ***, P ≤ 0.0005.