FIG 3 .
Evaluation of the glycoproteins isolated from animal experiments. (A) Purified CTB4573C-OPS and rEPA4573N-OPS were separated by 12% and 10% SDS-PAGE, respectively. The proteins were then stained by Coomassie blue, and the OPSs were visualized by PAS staining. (B) For analysis with SEC-HPLC (TSK G4000SWXL, diameter [φ], 7.8 × 300 mm), 25 µl of purified glycoproteins was added, and the mobile phase consisted of 50 mM phosphate buffer and 0.9% NaCl. (C) The IgG subtype titers (IgG1, IgG2a, IgG2b, and IgG3) against the LPS from S. flexneri 2a strain 301 were measured in the serum of BALB/c mice immunized with CTB4573C-OPS, rEPA4573N-OPS, OPS, or adjuvant alone. Data are shown as points, and the lines indicate the means. Compared with the OPS group by t test, t was 15.4 for CTB4573C-OPS and t was 2.76 for rEPA4573N-OPS (*, P < 0.05; ***, P < 0.0001). (D) Complement bactericidal activity in different dilutions of serum from the mice vaccinated with CTB4573C-OPS. The error bars indicate the range for the percentage of deaths. (E) Mice that had been vaccinated as described for panel C were infected intraperitoneally with approximately 3 × 107 CFU/mouse of S. flexneri 2a strain 301, and their survival was monitored. (F) BN-PAGE analysis of CTB4573C-OPS and rEPA4573N-OPS.