(A–C) Proportion of ST2 (A), ST4 (B), and ST23F (C) S. pneumoniae bacteria positive for C1q after incubation in 90 μg/ml human C1q with or without addition of 10 or 50 μg/ml hSAP.
(D) Example of flow cytometry histograms of C1q binding to ST4 S. pneumoniae after incubation in 90 μg/ml human C1q with or without addition of 50 μg/ml hSAP.
(E) Proportion of S. pneumoniae positive for C1q after incubation in human serum with (black shading) or without (grey shading) addition of 50 μg/ml hSAP, using C1q-depleted serum (white shading) as a negative control.
(F) Example of flow cytometry histograms of C1q binding to ST2 S. pneumoniae after incubation in human serum with or without addition of 50 μg/ml hSAP.
For panels (A–C) and (E), error bars represent SDs, and p-values are calculated using 2-tailed t tests.