FIG. 1.

(A and B) Deposition of complement C3 on the surface clinical pneumococcal isolates (A) and pneumococcal reference strains used in the opsonophagocytic assay (B). C3 deposition is expressed as the geometric mean intensity of fluorescence (GMF) with 95% confidence intervals from analyses with eight different normal human sera (NHS). The number of clinical isolates analyzed per serotype is shown outside the bar, and the geometric mean of the GMF values is shown inside the bar. The serotype 6B and 19F clinical isolates, indicated with an asterisk, were analyzed in a previous study with four different normal human sera (33).