Purification and characterization of the 1q subcomponent of canine complement and its use in the 125I-C1q binding assay for detection of immune complexes.
The complement subcomponent, C1q, was isolated from serum obtained from clinically normal dogs, using a rapid 2-step process involving affinity chromatography. Yield of C1q ranged from 8 to 10 mg/L of serum. Hemolytically active C1q had 3 protein bands after sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions and formed a single line of identity with rabbit anti-canine C1q. The amino acid composition of canine C1q was similar to that of human C1q and contained a high percentage of glycine. Isolated canine C1q was iodinated, and the fluid-phase binding assay was used to detect circulating immune complexes in dogs with systemic lupus erythematosus and rheumatoid arthritis.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000936:Antigen-Antibody Complex / Q000032:analysis*; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000662:veterinary; D002846:Chromatography, Affinity; D003166:Complement Activating Enzymes / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*; D003172:Complement C1 / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*; D015922:Complement C1q; D004283:Dog Diseases / Q000175:diagnosis; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D006462:Hemolytic Plaque Technique; D005779:Immunodiffusion; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000662:veterinary
D000596:Amino Acids; D000936:Antigen-Antibody Complex; D003172:Complement C1; D015922:Complement C1q; D003166:Complement Activating Enzymes