Figure 3.

pCRP facilitates phagocytosis of S. pneumoniae-FITC targets by opsonization, while mCRP does not. Phagocytosis by neutrophils (A), classical, and non-classical monocytes (B) was assessed by the described flow cytometry protocol. FITC-tagged S. pneumoniae incubated with 100 µg/mL pCRP before exposure to phagocytic cells were engulfed significantly faster and in higher amounts compared to an untreated control in all three subtypes investigated (A, B). mCRP added to the target suspension in the same concentration showed no significant effects on the phagocytosis in all assessed subtypes and time-points (C, D). All results are presented as means and S.E.M. and P values were calculated with ANOVA and Tukey post hoc test, n = 4, * and ** P < 0.05 and < 0.01.