Detection of rheumatoid-like factors in serum of chickens immunized with bacterial immunoglobulin binding proteins

A simple, rapid two-stage competitive binding radioimmunoassay is described for detecting rheumatoid factor-like antibodies in the serum of chickens immunized with bacterial immunoglobulin binding proteins. The assay could be adapted to determine the species specificity of any rheumatoid factor-like antibody by changing the species of immobilized IgG used. This assay has important practical implications for selecting suitable antibodies for detection of bacterial immunoglobulin binding proteins leaching from affinity columns in the presence of a large molar excess of IgG, and in determining the relationship between antibodies to bacterial IgG binding proteins and rheumatoid factor production.