A simple and sensitive fluorometric immunoassay for the measurement of immunoglobulins in culture medium of mitogen-stimulated lymphocytes

A sensitive fluorescent immunoassay (FIA) for the quantification of immunoglobulins (IgG, IgM) in culture supernatants of human lymphocytes has been developed and compared with an ELISA method. FIA, like the ELISA assay, detects nanogram amounts of immunoglobulin (Ig), and has a high degree of specificity and reproducibility. The intra-assay coefficient of variation was about 5% in both test systems; the inter-assay coefficient of variation was approximately 9% in FIA and 13% in ELISA. Quantification of supernatants of lymphocyte cultures by both systems showed a high degree of concordance (correlation coefficient r = 0.93). The advantages of the FIA procedure are the short assay time and the more direct acquisition of signal.