Resistance of Neisseria gonorrhoeae Grown in vivo to Ingestion and Digestion by Phagocytes of Human Blood

Abstract

S U M M A R YAttempts to study quantitatively the phagocytosis of gonococci from urethral pus failed because of the small numbers of organisms and technical difficulties. However, gonococci from chambers implanted subcutaneously in guinea pigs, which were similar to gonococci from urethral pus in their resistance to killing by human serum, were obtained in sufficient quantities for comparison in phagocytosis tests with the in vitro grown strain from which they were derived.Microscopic and viable counts of gonococci in phagocytes showed that in vivo grown organisms (strain BSV) were readily phagocytosed by human polymorphonuclear phagocytes. There was little difference between BSV organisms and the in vitro grown organisms (strain BS) in resistance to ingestion. There was, however, a marked difference in the intracellular survival of strains BSV and BS during the first hour of phagocytosis. Whereas BSV organisms survived well, many BS organisms were killed. Subsequently, strain BSV and the survivors of the strain BS inoculum responded similarly to the intracellular bactericidins. These results were supported by electron microscopy of infected phagocytes.Resistance of gonococci in vivo to ingestion and digestion by human phagocytes seem to be important facets of the pathogenesis of gonorrhoea. INTRODUCTIONStrongly staining gonococci are seen both extracellularly and intracellularly in urethral pus from patients with gonorrhoea. The presence of extracellular organisms suggests overloading of phagocytic capacity and indicates that some gonococci in vivo may resist phagocytosis. However, the presence of intracellular organisms shows that phagocytosis occurs and, further, that gonococci may resist the intracellular bactericidins. Thus resistance to ingestion and digestion by polymorphonuclear phagocytes (PMN phagocytes), the predominant cell type in urethral pus, would be important in acute infection; and survival inside the fewer mononuclear phagocytes (MN phagocytes) could be important in chronic infection.Pilated (Dilworth et al., 1975). Thus, resistance to ingestion appears to be correlated with the virulence for man of the Kellogg types, but whether or not pili are responsible for the resistance is still a matter of dispute (Swanson et al., 1974).With regard to resistance to intracellular killing, appreciable numbers of a pilated, small-colony-forming strain of gonococcus (BS) resembling Kellogg type 2 survived and multiplied within human buffy-coat phagocytes (predominantly PMN phagocytes) over I 5 h and also survived for at least 6 h in the few MN phagocytes that could be separated from the buffy coat (Veale et al., I 976). A non-pilated, large-colony-forming strain (AL) resembling Kellogg type 4 survived at a much lower level than the BS strain and was destroyed in 10 to 12 h (Veale et al., 1976). Thus, with strains BS and AL, resistance to digestion could be correlated with infectivity for guinea-pig chambers (Veale et al., 1975) and, by analogy with the Kellogg types, with potential virulence for man. These...

The Role of Outer Membrane Proteins in the Survival of Neisseria gonorrhoeae P9 within Guinea-pig Subcutaneous Chambers

“…Thus, the selection of variants with particular opacity-related proteins is in accord with previous observations that guinea-pig chamber gonococci were antigenically distinct from the same strain grown on laboratory media (Penn et al, 1978) and showed enhanced resistance to host defences Witt et al, 1976). The results from the present study demonstrate that additional, presumably antigenic, proteins are indeed present in gonococci obtained from guinea-pig chambers and that these can be maintained by careful colony typing during growth in vitro.…”

Interaction of Mycoplasma Pulmonis With Mouse Peritoneal Macrophages and Polymorphonuclear Leucocytes

“…In all three experiments the killing of mycoplasmas grown in vivo by macrophages was significantly less than that of organisms grown in vitro; this difference did not appear to depend on the numbers of mycoplasmas attached to the macrophages at the start of the experiment. Possible explanations for these differences are (1) that the uptake of both mycoplasma preparations by macrophages is the same, but the intracellular killing of in-vivo-grown organisms is less efficient as seen for in-vivo-grown Neisseria gonorrhoeae in human phagocytes (Witt et al, 1976); (2) that there may be changes in the antigenic structure of mycoplasmas replicating in vivo, or (3) that host material or non-opsonic antibody or both may be bound to the mycoplasma and inhibit the attachment of opsonic antibody to the organism. There is some evidence that mycoplasmas can selectively "acquire" host antigens, and these may hinder their recognition by the host's defence mechanisms (Wise, Cassell and Acton, 1978).…”

Immune-enhanced Phagocytosis of Neisseria gonorrhoeae by Macrophages: Characterization of the Major Antigens to which Opsonins are Directed

“…However, not all investigators have been able to demonstrate such antibody (Roberts, 1977). Furthermore, apparent survival of gonococci inside phagocytic cells has been reported (Evans, 1977;Witt et al, 1976) suggesting that phagocytosis might occasionally lead to a focus for persistent infection.…”