Complement-component-C3-opsonized immunoglobulin G anti-DNA antibodies do not bind effectively to red blood cells unless aggregated on a high-Mr DNA matrix.
Large, soluble ds (double-stranded) DNA-IgG (immunoglobulin G) anti-dsDNA immune complexes (greater than or equal to 200 S) that were previously opsonized with complement were digested with DNAase. The small complement-component-C3-fragment-labelled IgG (11-14 S) that was then isolated did not bind effectively to complement receptor type 1 on human red blood cells. However, when this IgG was immune-complexed with 3H-labelled PM2 (bacteriophage directed against a marine Pseudomonas) dsDNA (Mr approximately 6 X 10(6), substantial binding of both the DNA antigen and IgG to the erythrocytes was demonstrable.
D000936:Antigen-Antibody Complex / Q000276:immunology*; D002499:Centrifugation, Density Gradient; D003176:Complement C3 / Q000276:immunology*; D004247:DNA / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D066298:In Vitro Techniques; D008970:Molecular Weight
D000936:Antigen-Antibody Complex; D003176:Complement C3; D007074:Immunoglobulin G; D004247:DNA