FIG 7.

Deposition of human C1q on live bacterial cells of wild-type group B strain H44/76, as measured by flow cytometry. The bacteria were incubated with human complement and 10 μg/ml of chimeric WT IgG3 or the hinge-truncated mutants IgG3m17 and IgG3m15 MAbs. Black solid lines, WT IgG3; gray solid lines, IgG3m15; black dashed lines, IgG3 M17; gray filled histograms, bacteria without MAb, used as a negative control. Similar respective results were obtained in two independent experiments (data not shown).