title: Properties and reactivity of immune complexes in rheumatoid synovial fluid.
abstract: Fractionation of immune complexes (IC) from rheumatoid synovial fluid revealed the presence of three different fractions of IC. The largest molecular weight form, fraction I (above 1000 Kdaltons) was predominately composed of IgG and IgM and contained both IgM-RF and IgG-RF. The other IC, fraction II (480 Kdaltons) and fraction III (330 Kdaltons), contained predominately IgG with some IgA and only significant amounts of IgG-RF. All three fractions of IC can bind Clq and stimulate human monocyte prostaglandin E (PGE) production. Fraction I IC bound Clq most readily while fraction III IC were the most effective stimulators of monocyte PGE production. IC stimulation of monocyte PGE production was inhibited by staphylococcus protein A suggesting mediation via activation of Fc receptors. It remains to be determined whether this IC reactivity has any pathologic significance.
mesh_terms: D000936:Antigen-Antibody Complex / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D003166:Complement Activating Enzymes / Q000276:immunology; D015922:Complement C1q; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D046911:Macromolecular Substances; D009000:Monocytes / Q000276:immunology*; D010003:Osteoarthritis / Q000276:immunology; D011458:Prostaglandins E / Q000096:biosynthesis; D012217:Rheumatoid Factor / Q000276:immunology; D013205:Staphylococcal Protein A / Q000276:immunology; D013582:Synovial Fluid / Q000276:immunology*
chemical_list: D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D046911:Macromolecular Substances; D011458:Prostaglandins E; D013205:Staphylococcal Protein A; D015922:Complement C1q; D012217:Rheumatoid Factor; D003166:Complement Activating Enzymes