Figure 5.

Protective effect of KST0555 immunization against Salmonella infections in mice. BALB/c mice (n=5) were orally immunized with KST0555 or PBS three times at two-week intervals. Serum levels of (A) Salmonella- or (B) LPS-specific total Ig, IgG and IgM were analyzed at 7 days following the last immunization. Data are representative of three independent experiments and are presented as the mean ± standard deviation. Subclass levels of (C) Salmonellaand (D) LPS-specific IgG1, IgG2a, IgG2b and IgG3 were analyzed at 7 days subsequent to the last immunization. Data are representative of three independent experiments and are presented as the mean ± standard deviation. Splenocytes isolated from mice were incubated with 10⁸ CFU of S. Typhimurium WT lysate for 72 h, and concentrations of (E) IFN-γ and (F) IL-4 were measured from culture supernatants using an enzyme-linked immunosorbent assay. Bars indicate the mean of results of triplicate wells of a representative experiment. Error bars indicate standard deviation. Immunized mice were challenged orally with 10⁷ CFU of WT at 7 days following the last immunization and (G) mouse survival and (H) body weight were monitored for 14 days. ^*P<0.05, ^**P<0.005 and ^***P<0.001 vs. PBS group. PBS, phosphate buffered saline; Ig, immunoglobulin; LPS, lipopolysaccharide; CFU, colony-forming units; WT, wild-type; IFN-γ, interferon-γ; IL-4, interleukin-4.