A new solid support for sandwich enzyme immunoassays of human immunoglobulin G.
Two antibodies were prepared for use in a sandwich enzyme immunoassay of human IgG. Completely purified guinea pig anti-human IgG was labelled with beta-D-galactosidase (EC 3.2.1.23), using a heterobifunctional cross-linker named GMBS. Partially purified anti-human IgG was immobilized on a new solid support: Amino-Dylark balls. Optimal conditions for immobilizing the antibody, using glutaraldehyde as the coupling reagent, were studied in detail. With the enzyme-labelled antibody and the solid-phase anti-human IgG, a sandwich enzyme immunoassay of human IgG with a lower limit of detection at 10.5 pM (0.3 ng/tube) was developed. A comparative study of the EIA method and a laser nephelometric method showed a good correlation. The specificity of the assay was excellent: all 4 types of IgG tested showed the maximum 0.0001%; human IgA, IgM and albumin possessed the maximum 0.54% in their cross-reactivity values with human IgG.
D000818:Animals; D000918:Antibody Specificity; D003429:Cross Reactions; D006168:Guinea Pigs / Q000276:immunology; D006736:Horses; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000032:analysis*; D007163:Immunosorbent Techniques; D051379:Mice; D011817:Rabbits; D013552:Swine; D001616:beta-Galactosidase
D007074:Immunoglobulin G; D001616:beta-Galactosidase