title: Protective mechanism of the immune response to a ribosomal vaccine from Pseudomonas aeruginosa. II. In vitro bactericidal and opsonophagocytic studies with specific antiserum.
abstract: In vitro bactericidal and opsonophagocytic assays were performed with mouse antiserum to a ribosomal vaccine from Pseudomonas aeruginosa. The results obtained demonstrated that both specific antibody and complement are required for bactericidal and opsonic activities. C4-deficient complement also supported these activities. Polymorphonuclear leukocytes (PMNL) are not required, but when present, augment the observed killing activity. Opsonic and bactericidal activities were found to increase with increasing complement concentrations in an apparently logarithmic fashion until maximal activity was obtained. On the contrary, determination of bactericidal activity as a function of specific antiserum concentration revealed a "prozone" effect; i.e., maximal activity was obtained at an intermediate concentration of antiserum with significantly decreased activity at both higher and lower concentrations. This effect was not observed when immunoglobulin G (IgG) purified from specific antiserum by a method involving exposure to pH 9.0 and pH 3.0 was used instead of whole antiserum. In this case bactericidal activity increased as IgG concentration was increased, also in an apparently logarithmic manner.
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D001428:Bacterial Vaccines / Q000276:immunology*; D003181:Complement C4 / Q000172:deficiency; D003165:Complement System Proteins / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D007106:Immune Sera / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology; D051379:Mice; D009504:Neutrophils / Q000276:immunology; D009895:Opsonin Proteins / Q000276:immunology*; D010587:Phagocytosis / Q000187:drug effects*; D011550:Pseudomonas aeruginosa / Q000276:immunology*; D012270:Ribosomes / Q000276:immunology*
chemical_list: D001428:Bacterial Vaccines; D003181:Complement C4; D007106:Immune Sera; D007074:Immunoglobulin G; D009895:Opsonin Proteins; D003165:Complement System Proteins