IMMUNOBIOLOGY OF PURIFIED RECOMBINANT OUTER-MEMBRANE PORIN PROTEIN-I OF NEISSERIA-GONORRHOEAE

Gonococcal porins (For) from strains FA19 (Por-1, serogroup A), MS11 ( Por-2, serogroup B) and FA6434 (Por-5, a hybrid porin containing epito pes from both serogroups), were expressed in Escherichia coli and puri fied under non-denaturing conditions. Porins were inserted into liposo mes, and they were bound by monoclonal antibodies which bind native Fo r and intact gonococci, but not denatured For. All three recombinant p orins (rPor) were highly immunogenic in rabbits without additional adj uvant. The rPor antisera were specific for For by Western blotting and whole-cell radioimmunoprecipitation and were broadly cross-reactive w ithin serogroups. Post-immune, but not pre-immune, sera bound to intac t gonococci, induced deposition of complement components C3 and C9 ont o gonococcal membranes and increased association with and activation o f human neutrophils. Gonococci were not killed in bactericidal assays, and there was no phagocytic killing with gonococci opsonized with rec ombinant antisera. Lack of killing in bactericidal assays was not caus ed by the presence of blocking antibodies to the outer-membrane protei n Rmp.