title: Macrophage-mediated killing of opsonized Treponema pallidum.
abstract: The ability of proteose peptone-induced normal rabbit peritoneal macrophages to kill Treponema pallidum subspecies pallidum in vitro is demonstrated. Treponemes and 10% heated immune or normal sera were incubated with macrophages at a ratio of 1:200. After 2-10 h of incubation, these mixtures were injected intradermally at duplicate sites on normal rabbits. Maximal killing (failure to develop lesions) was seen at 10 h of incubation with immune serum: Only 7% (1/14) of lesions developed compared with 90% (9/10) after incubation in the presence of normal serum (P less than .001). Maximal phagocytosis (detected by immunofluorescence) occurred by 8 h in the presence of immune serum, when 90% of macrophages had ingested treponemes. At this point, however, 70% of lesion sites from macrophages incubated with treponemes and immune serum still developed, suggesting that effective killing may require at least 2 h after phagocytosis.
authors.affiliation: Department of Medicine, University of Washington School of Medicine, Seattle.
authors.forename: S A
authors.initials: SA
authors.lastname: Baker-Zander
authors.forename: S A
authors.initials: SA
authors.lastname: Lukehart
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D015151:Immunoblotting; D008264:Macrophages / Q000276:immunology*; D008297:Male; D009895:Opsonin Proteins / Q000276:immunology*; D010587:Phagocytosis; D011817:Rabbits; D014210:Treponema pallidum / Q000276:immunology*
chemical_list: D007106:Immune Sera; D009895:Opsonin Proteins