A quantitative ELISA for IgG in cell culture supernatants

The measurement of IgG, using a sandwich-type enzyme-linked immunosorbent assay (ELISA), is described. The assay is specific, sensitive, and simple to perform. Purification of the antibody, prior to attachment to the plastic solid phase, results in a more sensitive test. Optimum standardisation of the reagents and conditions is described and discussed. The assay is capable of detecting IgG to 2.5 X 10(-5) IU/ml (approximately equal to 3 ng/ml) and is useful for measuring IgG produced by cells in culture. The coefficient of variation within assays is 6.0% and between assays is 7.7%.