FIG 2.

Both OMV and LPS from mutant strains of V. cholerae lack O antigen. (A) Protein and LPS content of outer membrane vesicles produced by mutant strains of V. cholerae. Five micrograms of OMVs with or without SDS and proteinase K (Prot. K) were incubated at 55°C overnight. An aliquot of 2.5 μg was loaded on a 4 to 12% gradient SDS-PAGE gel. After electrophoretic separation, the gel was stained with silver. (B) Ten microliters of serial dilutions of purified LPS from wild-type O1 El Tor E7946, a rough mutant derivative (ΔwbeL), and O139 serogroup strain MO10 were spotted in triplicate onto a nitrocellulose membrane and air dried. The membrane was probed using primary anti-O1-antigen antibody and Cy5-conjugated, anti-IgG secondary antibody.