Fig. 5.

Minor pilins SpaB and SpaC required for bacterial adherence.

A and B. The parental strain SpaABC⁺ (ΔsrtB–F) and its isogenic deletion mutants were subjected to adhesion assays using pharyngeal epithelial cells (A) or lung epithelial cells (B). Data are presented as percentage of adhesion relative to that of the parental strain. The results are presented as averages (with standard deviations ± SD) from at least three independent experiments performed in triplicates. Statistical analysis was performed using Student’s t-test.

C. In a similar experiment as described in (A), monolayer of pharyngeal epithelial cells were infected with the parental strain SpaABC⁺ pre-incubated with a specific antiserum at a dilution of 1:100 for 1 h at 37°C. Pre-immune sera and an unrelated antibody against a pilus protein of Streptococcus agalactiae, α-GBS59, were used as controls.