A novel sORF gene mutant strain of Yersinia pestis vaccine EV76 offers enhanced safety and improved protection against plague
Fig 5
Humoral immune responses in mice administrated s.c. with the EV76-derived candidate vaccines in short-term study.
Mice (n = 10 per group) were immunized s.c. with two doses of 5×106 CFU of EV76, EV76Δyp2, EV76Δyp1 or EV76Δyp1&yp2 at a 21-day interval. Sera were collected on day 41 after the initial immunization. Titers of IgG specific to F1 (A), LcrV (B), and 201Δcaf1-WCL (C) were measured using ELISA. (D) For Western blotting analysis, blotted antigens were obtained from the whole cell lysates of 201 or 201Δcaf1, and pooled sera from immunized mice were used as primary antibodies. (E) IgG subclasses to 201-WCL antigen were analyzed by ELISA. (F) The serum IgG2a/IgG1 ratios in the immunized mouse groups were determined. Statistical analysis was conducted using One-way ANOVA with Tukey post hoc to determine the significance of differences. *P<0.05, **P<0.01, ***P<0.001 and ****P<0.0001.