Specific agglutination of polyacrylamide derivatives of protein antigens

Abstract

Proteins such as β-lactoglobulin, bovine serum albumin, α-lactalbumin, and bovine γ-globulin were coupled by covalent bonds to crosslinked copolymers of acrylamide and methyl acrylate through reaction with azide derivatives of the methyl acrylate residues. Substantial amounts of proteins (1–5 mg/100 mg polymer) were bound to the surface of the copolymer particles. The use of these derivatives to assay for the specific antibodies in rabbit antisera was tested. Specific agglutination of the protein derivatives was obseved with antisera containing as little as 0·05 μg antibody per ml. Antibody titers against the protein derivatives as high as 1:10,000 were retained on storage of the polymer-protein derivatives at 4°C in saline solutions for 3 months. The protein derivatives removed specific antibodies from immune sera.