FIG. 3.

Western blot analysis of S. pneumoniae strains. SDS-10% polacrylamide gels were loaded with rPsaA (A), rPpmA (B), or rPspA (C) (all derived from strain A66.1 coding sequences) as positive controls (+), S. enterica serovar Typhimurium lysate as a negative control (A to C, −), and S. pneumoniae lysates from strain A66 and the strains described in Table 1 and indicated by their serotypes. Electrophoresed proteins were transferred to polyvinylidene difluoride membranes and incubated with polyclonal anti-PsaA (A), anti-PpmA (B), or anti-PspA (C). Blots were developed with alkaline phosphatase-conjugated goat anti-mouse IgG (γ-chain specific) and visualized by incubation in BCIP-NBT chromogenic substrate. Apparent molecular size markers in kilodaltons are indicated.