Immunoblot analyses of the wild type PrtV protein and its PKD domain deletion mutant in culture supernatants and OMV samples.

Immunoblot analysis was performed using anti-PrtV antiserum (A) and anti-OmpU antiserum (B) with the following samples: lanes 1–3: V. cholerae ΔprtV strain carrying the cloned wild type allele of prtV; lanes 4–6: the ΔprtV strain carrying the cloned prtVΔPKD allele; lanes 7–9: the ΔprtV strain carrying the pBAD18 cloning vector. Lanes 1, 4 and 7 were loaded with supernatant samples before ultracentrifugation (Sup1). Lanes 2, 5 and 8 were loaded with the supernatants after ultracentrifugation (Sup2). Lanes 3, 6 and 9 were loaded with the OMV samples.