An enzyme-linked immunosorbent assay for the quantification of solubilized CD14 in biological fluids

A simple and robust two site-binding ELISA for the quantification of solubilized CD14 in human and animal body fluids is described. The principle of the assay depends on the specific binding of sCD14 to two monoclonal antibodies (MEM-18, RoMo-1) recognizing different epitopes of this glycoprotein. The detection limit for sCD14 was 1 ng/ml. The method was used to quantify sCD14 in different biological fluids, giving an intra-assay coefficient of variation and an interassay coefficient of variation of about 9%. The assay was used to measure sCD14 in human serum and plasma and other body fluids in health and disease, and in cell culture supernatants. With the exception of monkeys there was no reactivity with 29 other species screened. In healthy volunteers the sCD14 serum level had a mean value of 3.98±0.3 μg/ml (mean SEM, n = 102).