Probing the surface of Neisseria gonorrhoeae: simultaneous localization of protein I and H.8 antigens.

Gonococcal outer membrane protein I and the neisserial antigen H.8 are being investigated for inclusion in a gonococcal vaccine. To determine the distribution of immunoaccessible protein I and H.8 molecules on the surface of viable gonococci and to approximate the accessibility of these antigens to vaccine-elicited antibodies, immunologic probes composed of protein I- and H.8-specific antibodies linked to gold spheres were developed. When whole gonococci were exposed to the protein I and H.8 immunologic probes and examined by transmission electron microscopy, gold spheres clearly marked the surface of some of the gonococci, but not the surface of other gonococci from the same culture. The immunologic accessibility of gonococcal protein I or neisserial H.8 varied among gonococci. This diversity may affect the efficacy of a vaccine composed of these surface antigens.