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Immunoglobulins G, A and M in Normal and Pathologic Human Sera Determined with the Spot Immunoprecipitate Assay (SIA) in Multi‐assay Plates
Author(s) -
WADSWORTH C.,
WADSWORTH E.
Publication year - 1979
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1979.tb02729.x
Subject(s) - radial immunodiffusion , antibody , antigen , antiserum , chemistry , immunoprecipitation , microbiology and biotechnology , immunodiffusion , chromatography , monoclonal antibody , immunology , biology
A simple rapid spot immunoprecipitate assay (SIA) is presented. The antigen‐antibody reaction takes place in a field of alternating current; small amounts of specific antisera are used and the influence of diffusion or electromobility of the antigen is avoided. Determinations of IgG, IgA and IgM in sera from healthy individuals correlated highly significantly with radial immuno‐diffusion (RID) results. The reaction conditions in SIA, particularly the availability of a sufficiency of specific antibodies, may permit more accurate estimates of monoclonal forms of Ig than in RID, where the combination depends on diffusion of one reactant. The precision of SIA quan‐titation of IgG and IgA was within ± 10% and ± 13% for IgM. Working ranges of the standard curves were from about 25–150 ng for G and A and 75–300 ng for IgM: least squares regression coefficients for four sets of standards on three SIA plates were 0.995 for IgG, 0.969 for IgA, and 0.986 for IgM. IgA at 7.5 ng in a 2.5 mg/1 dilution was at the lower limit of demonstrability. Photometric registrations and estimates made by visual inspection compared highly significantly ( P <0.001), differing by ±13%.