FIGURE 7.

C1q acts as a bridge between the C‐SSURE domain and α₂β₁ integrin in mediating pneumococcal adhesion. (a) Interactions between C1q, recombinant SSURE domains (C‐SSURE or N‐SSURE), and α₂β₁‐integrin in ELISA assays. Binding was detected with anti‐C1q (black column) or anti SSURE antibodies. Shown are means ± SDs of three independent experiments conducted in triplicate. (b) Inhibitory effect of anti‐α₂β₁ antibodies on C1q‐mediated adhesion. Monolayers of respiratory epithelial cells (A549) were pretreated with antibodies against α_Vβ₃ or α₂β₁ integrins before being infected with bacteria in the presence (10 μg) or absence of C1q. Adhering bacteria were measured by colony‐forming units (CFU) counts. Shown are means ± SDs of three independent experiments conducted in triplicate. *p < 0.05 by Mann–Whitney test.