Parallelism of serum anti-F(ab')2 and anti-cationic IgG reactivities in patients with systemic lupus erythematosus.
Cationic anti-DNA antibodies may be related to glomerular injury in murine lupus nephritis or in patients with systemic lupus erythematosus (SLE). Therefore, anti-cationic antibodies in SLE could include antibodies with regulatory function on such pathogenic cationic molecules. Since anti-F(ab')2 antibodies may be involved in the idiotype control of anti-DNA antibodies in some patients with inactive SLE, the present study was aimed to determine if SLE patients with significant serum levels of anti-F(ab')2 produce antibodies reacting with cationic IgG molecules. Three SLE sera with high titers of anti-F(ab')2 antibodies were individually adsorbed by sequential affinity chromatography on three Sepharose columns coupling normal IgG from Cohn Fraction II, pooled cationic IgG myeloma paraproteins displaying idiotypic anti-DNA markers (F4 and 8.12), and F(ab')2 fragment from allogeneic IgG, respectively. Eluates obtained from cationic IgG adsorption showed predominant anti-F(ab')2 reactivity. A similar profile was also detected in a serum from a normal control donor with high levels of anti-F(ab')2. Biotinylation of anti-cationic eluates showed that such antibodies were significantly more reactive with cationic than anionic or neutral IgG, confirming their apparent affinity for positively charged antigens on IgG molecules. Since anti-cationic absorptions were able to remove the anti-F(ab')2 activities in the SLE sera studied, it is possible that anti-cationic antibodies could function as immunoregulatory antibodies in the idiotypic control of some SLE autoreactive phenomena, including glomerular anti-DNA deposition.
Silvestris
F
F
Division of Rheumatology and Clinical Immunology, University of Florida, Gainesville 32610.
Yancey
W B
WB
Malone
C
C
Searles
R
R
Dammacco
F
F
Williams
R C
RC
D000328:Adult; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis*; D000974:Antibodies, Antinuclear / Q000032:analysis; D001710:Biotin / Q000276:immunology; D002846:Chromatography, Affinity; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology*; D007141:Immunoglobulin Fc Fragments / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008875:Middle Aged; D009194:Myeloma Proteins / Q000032:analysis
D000888:Antibodies, Anti-Idiotypic; D000974:Antibodies, Antinuclear; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D009194:Myeloma Proteins; D001710:Biotin