title: Gonococci in vivo and in vitro. Further studies on the host and bacterial determinants of gonococcal resistance to killing by human serum, and by phagocytes.
abstract: A small M, heat and acid labile, host inducer(s) of gonococcal resistance to complement mediated killing by fresh human serum (-FHS), being purified from red blood cell (RBC) extracts, produced changed in lipopolysaccharide (LPS) structure, surface antigens and proteins; and acquirement of resistance related to loss of a target antigen for bactericidal IgM, possibly LPS components. A 20 kDalt. lipoprotein with a high content of glutamic acid isolated from outer membranes of a gonococcal strain selected in vivo is a determinant of gonococcal resistance to killing by human phagocytes. Sonic extracts of gonococci may contain a cytotoxin for human phagocytes. At the 4th International Pathogenic Neisseriae Conference, we reported (Parsons et al. 1985) that conditions in vivo induced phenotypic change leading to gonococcal resistance to complement-mediated killing by human serum; and, also, selected gonococcal types which showed a greater resistance to intracellular killing by human phagocytes than laboratory strains. Furthermore, evidence was presented that not only was resistance to complement mediated killing important in gonococcal pathogenesis, but also resistance to phagocytic defences. This paper describes the continuance of our studies on the determinants of induced serum resistance and of resistance to killing by phagocytes including toxicity to these cells. Each section begins by summarising previous work that was referenced in Parsons et al. (1985).
mesh_terms: D000818:Animals; D001770:Blood Bactericidal Activity; D003165:Complement System Proteins / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000032:analysis / Q000276:immunology; D006168:Guinea Pigs; D006801:Humans; D009344:Neisseria gonorrhoeae / Q000032:analysis / Q000276:immunology*; D010586:Phagocytes / Q000276:immunology*
chemical_list: D003165:Complement System Proteins