What proteins are present in polyethylene glycol precipitates from rheumatic sera?
The proteins present in 4% polyethylene glycol (PEG) precipitates of 10 normal sera and 60 samples from patients with rheumatic diseases were studied. A variety of immunochemical methods were used, including estimation of the percentages of total serum proteins precipitated by PEG, gel filtration analyses of the precipitates, and affinity chromatography with protein A and anti-immunoglobulin columns. Substantial amounts of protein were precipitated from normal sera. Many non-immunoglobulin proteins were precipitated from patients' sera, including fibronectin, haptoglobin, albumin, transferrin, and alpha 1-antitrypsin. Affinity chromatography with anti-immunoglobulin columns bound non-immunoglobulin proteins from PEG precipitates, but the protein A affinity column did not do so. The view that circulating antibody-antigen complexes alone are precipitated by 4% PEG is too simplistic; many non-immunoglobulin proteins are involved. They may either bind to immune complexes or be coprecipitated owing to non-specific protein aggregation.
Robinson
M W
MW
Department of Rheumatology, Medical School, University of Birmingham.
Scott
D G
DG
Bacon
P A
PA
Walton
K W
KW
Coppock
J S
JS
Scott
D L
DL
D000293:Adolescent; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood; D001798:Blood Proteins / Q000032:analysis*; D011232:Chemical Precipitation; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D003240:Connective Tissue Diseases / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols; D012595:Scleroderma, Systemic / Q000097:blood; D014657:Vasculitis / Q000097:blood
D001798:Blood Proteins; D011092:Polyethylene Glycols