Investigation of the determinants of the survival of Neisseria gonorrhoeae within human polymorphonuclear phagocytes.

In studies aimed at identifying the determinants responsible for the ability of gonococci to survive and grow within human phagocytes, the reduction of intracellular survival of phagocyte-resistant gonococci by prior treatment of the bacteria with homologous antiserum provided two indirect means of testing for possible determinants. First, surface washes of the resistant gonococci and fractions of these extracts were examined for ability to neutralize the above effect of antisera. Second, antisera raised to purified surface components of the resistant organisms were examined for ability to promote intracellular killing. A combination of these methods indicate that the aggressins were not pili but components of the outer membrane. A surface wash of a phagocyte-resistant, pilated strain, BS4 (agar), neutralized the activity of homologous antisera before and after centrifuging at 20 000 g, but pili separated from the supernatant did not. A corresponding supernatant from the surface wash of a phagocyte susceptible strain, BSSH, had little neutralizing ability. Antisera to pili failed to reduce intracellular survival of resistant gonococci, whereas antisera against outer membrane vesicles did so. Finally, the neutralizing activity of the surface wash supernatant was removed by centrifugation after treatment with wheat germ agglutinin, which precipitates outer membrane vesicles.