Cationic and high affinity serum IgG anti-dsDNA antibodies in active lupus nephritis.
To investigate differences between cationic anti-dsDNA antibodies during active and inactive nephritis, low- and high-affinity IgG anti-dsDNA antibodies were prepared from sera of a lupus patient and compared for their binding affinity, spectrotype, and idiotype expression. The ratio of high-affinity to low-affinity anti-DNA antibodies and the relative avidity of the high-affinity anti-DNA antibodies decreased when active nephritis became inactive. Isoelectric focusing showed that cationic anti-dsDNA populations were present predominantly in the high-affinity fraction during active nephritis and in the low-affinity fraction during inactive nephritis. Idiotypic analysis by ELISA and Western blotting showed that the high-affinity cationic anti-DNA antibodies during active nephritis were idiotypically different from their low-affinity counterparts during inactive nephritis. The differences in binding affinity and idiotypy of the cationic anti-dsDNA antibodies suggest that certain serum IgG anti-dsDNA antibodies with both cationic charge and high affinity may be associated with active nephritis.
Suenaga
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Immunology Research Laboratory, St. Luke's Hospital, Kansas City, MO 64111.
Abdou
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D000974:Antibodies, Antinuclear / Q000097:blood*; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D005260:Female; D015432:Glomerulonephritis, Membranoproliferative / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007130:Immunoglobulin Idiotypes / Q000276:immunology; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D008181:Lupus Nephritis / Q000276:immunology*
D000974:Antibodies, Antinuclear; D000939:Epitopes; D007074:Immunoglobulin G; D007130:Immunoglobulin Idiotypes