title: Complement-activating properties of some rat alloantibodies.
abstract: The complement-activating property of immune sera, and of separated 19S and 7S antibody fractions, was examined with a number of rat histocompatibility antigen-alloantibody systems. It was confirmed that xenogeneic sera are very efficient sources of complement in the in vitro immune cytolysis of rat lymphocytes and erythrocytes by the alloantibodies of 19S and 7S classes. However, with allogeneic complement only 7S alloantibodies were able to lyse rat lymphocytes, and none of several alloimmune sera, nor any fractions derived from them, lysed allogeneic erythrocytes. The evidence suggests that the popular notion that IgM antibodies, as a class, are more efficient than IgG molecules in complement-mediated cell lysis may need qualification as to the source of complement and the type of target cell used in a given-experimental system.
mesh_terms: D000818:Animals; D005591:Chemical Fractionation; D003165:Complement System Proteins; D003601:Cytotoxicity Tests, Immunologic; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D006168:Guinea Pigs / Q000276:immunology; D006461:Hemolysis; D006649:Histocompatibility Antigens; D007106:Immune Sera; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007518:Isoantibodies; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D011817:Rabbits / Q000276:immunology; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D011919:Rats, Inbred Strains
chemical_list: D006649:Histocompatibility Antigens; D007106:Immune Sera; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007518:Isoantibodies; D003165:Complement System Proteins