下面以测定IL-1为例说明其原理。

　　Enzyme-linked immunosorbent assay for quantitative detection of mouse Interleukin-1 PRINCIPLES OF THETEST

　　1. An anti-mIL-1　monoclonal coating antibody is adsorbed onto microwells.

　　2. mIL-1　present in the sample or standard binds to antibodie sadsorbed to the microwells；a biotin-conjugated monoclonal anti-mIL-1 antibody is added and binds to mIL-1 captured by the first antibody.

　　3. Following incubation unbound biotin-conjugated anti-mIL-1?is removed during a wash step. Streptavidin-HRP is added and binds to thebiotin conjugated anti-mIL-1. Following incubation unbound Streptavidin-HRP is removed during a wash step, and substrate solution reactive with HRP is added to the wells.

　　4. A coloured product is formed in proportion to the amount of mIL-1 present in the sample. The reaction is terminated by addition of acid and absorbance is measured at 450nm. A standard curve is prepared from seven mIL-1?standard dilutions and mIL-1 sample concentration determined.