Characterization of Serum Resistance of Neisseria gonorrhoeae that Disseminate: ROLES OF BLOCKING ANTIBODY AND GONOCOCCAL OUTER MEMBRANE PROTEINS

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Abstract

Neisseria gonorrhoeae isolated from patients with disseminated infection (DGI) often resist complement (C′)-dependent killing by normal human serum (NHS) and less commonly by convalescent DGI serum. 7 of 10 NHS specimens completely inhibited killing of serum-resistant (serr) gonococci by convalescent or immune DGI serum. Immunoglobulin G (IgG) purified from NHS was shown to be the blocking agent. In addition, IgM (plus C′) purified from NHS was shown to be fivefold more effective (wt/wt) in killing serum-sensitive (sers) gonococci than equivalent amounts of IgM tested in the presence of IgG (whole serum). Although inhibition of NHS killing of sers gonococci required a 640% excess of IgG, only a 40% excess was required to block immune serum killing of serr gonococci. F(ab′)2 prepared from IgG also blocked killing of serr gonococci by immune serum indicating antigenic specificity of blocking IgG.

Authors

Peter A. Rice, Dennis L. Kasper