IgM rheumatoid factor and the inhibition of covalent binding of C4b to IgG in immune complexes.
Work by other investigators has shown that IgM-rheumatoid factors (IgM-RF's) can impede complement-mediated inhibition of immune precipitation. We examined the binding of complement component C4b to radiolabelled IgG in model immune complexes and demonstrate that IgM-RF's are capable of reducing the covalent binding of C4b to 125I-IgG in the complexes. Reduced binding to IgG, however, may not be accompanied by binding of C4b to IgM-RF's within the complex, as we also demonstrate that IgM-RF's are relatively poor at C4b capture compared with normal IgM.
James S. McDonnell Department of Genetics, Washington University School of Medicine, St. Louis, Missouri.
J N
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Jarvis
J C
JC
Lockman
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Levine
D000936:Antigen-Antibody Complex / Q000378:metabolism*; D001172:Arthritis, Rheumatoid / Q000276:immunology; D002850:Chromatography, Gel; D015935:Complement C4b / Q000276:immunology / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism*; D007075:Immunoglobulin M / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D007457:Iodine Radioisotopes; D011485:Protein Binding; D012217:Rheumatoid Factor / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*
D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007457:Iodine Radioisotopes; D015935:Complement C4b; D012217:Rheumatoid Factor