FIG. 3.

Factor H binds only to gonococcal strains (398 and 398079) bearing sialylated lacto-N-neotetraose (3F11) LOS, but not to strain 398078 bearing sialylated L1 LOS. (Upper panel) Factor H binding to strains 398 (LNT and L1 LOS), 398078 (L1 LOS), and 398079 (LNT LOS) grown either without CMP-NANA (histogram represented by thin solid line) or in media containing 1 μg/ml (bold line) or 100 μg/ml (gray shaded histogram) CMP-NANA was quantified by flow cytometry. (Lower panel) Factor H binding to lst mutants of 398, 398078, and 398079 grown with (100 μg/ml; gray shaded histogram) or without CMP-NANA. The x axis represents fluorescence, and the y axis denotes the number of events. Isotype controls (antibodies alone, no factor H) are shown in each plot by thin broken lines. One representative experiment of duplicate experiments is shown.