Human anti-idiotypic antibody responses to autoantibody against the alternative pathway C3 convertase.
Anti-idiotypic antibodies to autoantibody against the alternative pathway C3 convertase (C3NeF) were isolated and purified from normal human serum as well as from serum from six patients with membrano-proliferative glomerulonephritis (MPGN). All preparations of anti-id antibody blocked C3NeF deposition on EC3bBb as well as C3NeF stabilization of EC3bBb functional activity. The Ka of these ant-id antibodies for C3NeF was 10(9) liters/mol which is comparable to the Ka of C3NeF for its antigen. In addition, 90% of anti-id antibody isolated from patients with MPGN and 20% isolated from normal individuals resembled Bb and bound to C3b as well as to antibody specific for the Bb portion of Factor B. These anti-id antibodies also resembled C3b and bound to antibody specific for the C3c portion of C3b. Immunization of rabbits with this latter form of anti-id antibody led to the production of functionally active C3NeF. These data indicate that C3NeF anti-idiotypic antibodies exist in two distinct forms, with and without internal imagery of C3bBb, and can occur in both normal individuals and patients with MPGN.
Department of Pediatrics, State University of New York, Health Science Center, Syracuse 13210.
R E
RE
Spitzer
A E
AE
Stitzel
G C
GC
Tsokos
D000888:Antibodies, Anti-Idiotypic / Q000032:analysis / Q000276:immunology*; D000915:Antibody Affinity; D001323:Autoantibodies / Q000032:analysis / Q000276:immunology*; D001666:Binding Sites, Antibody; D003166:Complement Activating Enzymes / Q000276:immunology*; D003178:Complement C3 Nephritic Factor / Q000276:immunology; D050577:Complement C3-C5 Convertases / Q000276:immunology*; D003179:Complement C3b / Q000378:metabolism; D003170:Complement Pathway, Alternative / Q000276:immunology; D015432:Glomerulonephritis, Membranoproliferative / Q000276:immunology; D006801:Humans
D000888:Antibodies, Anti-Idiotypic; D001323:Autoantibodies; D003178:Complement C3 Nephritic Factor; D003179:Complement C3b; D003166:Complement Activating Enzymes; D050577:Complement C3-C5 Convertases