title: Inhibition of human factor B activity of the properdin system by human and guinea-pig sera.
abstract: The activity of factor B of the alternative pathway of complement activation was assayed in human and guinea-pig sera using the radial haemolytic assay with various MgCl2 and RB concentrations. RB were prepared by heating at 50 degrees C human or guinea-pig sera to render them deficient in factor B. Whatever concentrated RB and MgCl2 were, guinea-pig sera seemed unable to react while human sera gave an haemolytic reaction with both human and guinea-pig RB. We described an inhibition of human factor B activity by human and guinea-pig RB under certain conditions. This inhibition is more pronounced in the case of guinea-pig RB.
mesh_terms: D000818:Animals; D003167:Complement Activation; D011415:Complement Factor B / Q000032:analysis*; D003170:Complement Pathway, Alternative; D004306:Dose-Response Relationship, Immunologic; D004792:Enzyme Precursors / Q000032:analysis*; D004912:Erythrocytes / Q000276:immunology; D006168:Guinea Pigs; D006462:Hemolytic Plaque Technique; D006801:Humans; D008274:Magnesium
chemical_list: D004792:Enzyme Precursors; D011415:Complement Factor B; D008274:Magnesium