Fig 4.
Anti-PspA immune response. (A) IgG antibody titer to rPspA1. Individual serum samples from mice (n = 6) immunized i.p. with rPspA1 conjugated to PS6B by reductive amination (PS6B-rPspA1) or with mPspA1 conjugated to PS6B-OCT (PS6B-OCT-mPspA1) were analyzed by ELISA and compared by one-way ANOVA with Tukey's multiple-comparison test. Sera from mice immunized with the respective coadministered components or with saline plus Al(OH)3 were used as controls. Asterisks indicate statistically significant differences (***, P < 0.0001). ns, nonsignificant differences. The results for all groups were significantly different from those for the saline-treated group (P < 0.0001). (B) Complement deposition on S. pneumoniae bacteria. An example of a flow cytometry histogram for C3 deposition is shown. S. pneumoniae strain 245/00 (serotype 14 and PspA clade 1) was incubated with sera from mice immunized with PspA clade 1 conjugated to PS6B or to PS6B-OCT. Sera from mice immunized with the respective coadministered components or with saline plus Al(OH)3 were used as controls.