Immunological Heterogeneity of Pili of Neisseria gonorrhoeae

Abstract

Sera of rabbits immunized with pili or formalized cultures of Neisseria gonorrhoeae contained pili antibodies. The reaction between pili and specific gamma globulin was followed by direct visual observation with an electron microscope. Using pili from 31 strains and antisera against three strains, only a few crossreactions between pili were observed. From this it is concluded that gonococcal pili are antigenically heterogeneous. However, serum raised with a T3 culture (with no detectable pili) contained antibodies against pili of the homologous T2 strain. It is proposed that the pilus antigen may exist in a form different from the typical pilus in gonococci.

The Preparation and Properties of Gonococcal Pili

“…This suggests that the preparations were not contaminated with gonococcal lipopolysaccharide whose carbohydrate contains, besides glucose, and galactose, glucosamine and heptose (Perry et al, 1975). Current evidence indicates that there is a large but undetermined number of serotypes of gonococcal pili (Novotny & Turner, 1975). The role of the sugar group in the antigenicity of the pilus remains to be determined.…”

“…The promise of this approach is shown by the reports of Brinton (1975) that the infectious dose of laboratory-grown gonococci for volunteers is raised several fold after immunization with pure pili. A serious difficulty in the preparation of a pilus vaccine is the demonstration of considerable serological heterogeneity among pili (Novotny & Turner, 1975). Buchanan & Pearce (1976) also demonstrated antigenic heterogeneity in the four gonococcal pilus preparations tested; in a radio-immunoassay the degree of shared antigenicity amongst these preparations was estimated to be < 2-5 % (w/w).…”

The Inability of Neisseria gonorrhoeae Pili Antibodies to Confer Immunity in Subcutaneous Guinea-pig Chambers

“…These were GC agar (Difco) plates with supplements (Kellogg et al 19631, and liquid GC medium as used previously (Novotny & Turner, 1975).…”

“…Neisseria gonorrhoeae StG2, StG4, StG6, StGI8 and StG38 of Novotny & Turner (1975) were used. The strains were kept as frozen suspensions in a liquid nitrogen container (LD 40, Union Carbide).…”

“…Immune electron microscopy using rabbit antisera showed that pili of different strains of N. gonorrhoeae are antigenically heterogeneous with cross-reactions occurring only rarely (Novotny & Turner, 1975). It was of interest to know whether serological cross-reaction in pili would reflect cross-protection in the guinea-pig model.…”