Biomaterial Database

An ultrasensitive radioligand assay for IgG using the protein A on Staphylococcus aureus bacteria. 1984

G J Tevaarwerk, and W F Clark, and C I Rose, and T A Moriarity, and C J Hurst

The purpose of this study was to develop a simple and sensitive assay to measure IgG. Human IgG was radiolabelled with 125Iodine and 7.5 ng was incubated with heat-killed Staphylococcus aureus bacteria (Cowan 1 strain). To replicate sets of tubes, increasing amounts of a standard IgG preparation were added. The samples were incubated at room temperature for two hours and separated by centrifugation. Using this assay it was found that the IgG concentration could readily be determined in one nanoliter or less of human serum. There was no significant cross-reactivity with IgA, IgE and IgM or the F(ab')2 fragment of IgG. Serial dilutions of normal human or SLE sera, rabbit or guinea pig sera, the Fc fragment of human IgG and a mouse monoclonal anti-human DNA antibody parallelled the dose response curve obtained with standard human IgG. The method correlated well (r=0.89) with a routinely used nephelometric method. The mean (+/- SD) IgG concentration in 20 normal subjects measured by this assay was 10 +/- 3.6 g/L.

UI	MeSH Term	Description	Entries
D007074	Immunoglobulin G	The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.	Gamma Globulin, 7S,IgG,IgG Antibody,Allerglobuline,IgG(T),IgG1,IgG2,IgG2A,IgG2B,IgG3,IgG4,Immunoglobulin GT,Polyglobin,7S Gamma Globulin,Antibody, IgG,GT, Immunoglobulin
D009391	Nephelometry and Turbidimetry	Chemical analysis based on the phenomenon whereby light, passing through a medium with dispersed particles of a different refractive index from that of the medium, is attenuated in intensity by scattering. In turbidimetry, the intensity of light transmitted through the medium, the unscattered light, is measured. In nephelometry, the intensity of the scattered light is measured, usually, but not necessarily, at right angles to the incident light beam.	Turbidimetry,Nephelometry,Turbidimetry and Nephelometry
D011869	Radioligand Assay	Quantitative determination of receptor (binding) proteins in body fluids or tissue using radioactively labeled binding reagents (e.g., antibodies, intracellular receptors, plasma binders).	Protein-Binding Radioassay,Radioreceptor Assay,Assay, Radioligand,Assay, Radioreceptor,Assays, Radioligand,Assays, Radioreceptor,Protein Binding Radioassay,Protein-Binding Radioassays,Radioassay, Protein-Binding,Radioassays, Protein-Binding,Radioligand Assays,Radioreceptor Assays
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013205	Staphylococcal Protein A	A protein present in the cell wall of most Staphylococcus aureus strains. The protein selectively binds to the Fc region of human normal and myeloma-derived IMMUNOGLOBULIN G. It elicits antibody activity and may cause hypersensitivity reactions due to histamine release; has also been used as cell surface antigen marker and in the clinical assessment of B lymphocyte function.	Protein A,Protein A, Staphylococcal