title: Human IgM antibodies do not activate guinea-pig complement after interaction with soluble antigen.
abstract: Activation of guinea-pig complement by human IgM antibodies after interaction with a particulate antigen is well established. Human IgM antibodies directed against meningococcal group-C capsular polysaccharide, however, were not able to fix guinea-pig complement in a classical complement fixation test with soluble antigen. In the same test, human complement was readily activated by these antibodies. This inability of human IgM antibodies to activate guinea-pig complement after interaction with soluble antigen was confirmed in other antigen systems. In contrast, efficient activation of both human and guinea-pig complement was found with the same antigen in a particulate form.
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D003167:Complement Activation; D003172:Complement C1 / Q000378:metabolism; D003168:Complement Fixation Tests; D003171:Complement Pathway, Classical; D006168:Guinea Pigs; D006461:Hemolysis; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology*; D009345:Neisseria meningitidis / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D012995:Solubility; D013045:Species Specificity
chemical_list: D000907:Antibodies, Bacterial; D003172:Complement C1; D007075:Immunoglobulin M; D011135:Polysaccharides, Bacterial; C037676:meningococcal group C polysaccharide