Milk-specific antibody measurement by elisa: development of an assay.

This paper describes the development of a simple, sensitive and specific enzyme-linked immunosorbent assay (ELISA) for the measurement of serum IgG, IgA and IgM antibodies to cow's milk protein. The specificity of this assay was determined by preparing immunosorbents of cow's milk and human serum albumin (HSA). Fractionation of the antiserum-enzyme label by gel filtration and affinity chromatography showed that the conjugate preparation contained moieties of antiserum-enzyme, and antiserum-enzyme polymers. The preparation also contained enzyme-enzyme and antiserum-antiserum conjugates. Purification of the labeled reagent did not improve the sensitivity. The reagents and conditions used have been analyzed for purposes of standardisation.