Radioimmunoassay of Human Epidermal Growth Factor-hEGF Levels in Human Body Fluids

Abstract

By immunizing rabbits with purified human epidermal growth factor (hEGF), which was synthesized by Escherichia coli constructed by a genetic engineering technique, high titer antiserum for hEGF was obtained. The antiserum has an excellent specificity to hEGFs {hEGF, hEGF [1-51], hEGF [1-47] and [Leu²¹] hEGF} and has almost no cross-reactivity with other biological peptides, such as mouse EGF and human platelet derived growth factor. Using radioiodinated hEGF, a radioimmunoassay (RIA) for hEGF was established by a double antibody-polyethylene glycol method. As little as 10 pg/tube of hEGF was successfully determined by the present RIA methods. The intra- and inter-assay coefficients of variation for hEGF in human plasma or serum were 2.4-4.9% and 3.7-6.2%, respectively. The hEGF levels in human body fluids determined by the present method were as follows : urine (11-100 ng/ml), serum (1.0-1.8 ng/ml), plasma (0.2-0.8 ng/ml), sperm (17-47 ng/ml), saliva (0.9-3.0 ng/ml) and tears (9.5-27 ng/ml).