[Enzymeimmunoassay of human interferon-alpha using monoclonal antibody]

Five monoclonal antibodies to human rIFN-alpha A have been obtained and used them in a sandwich enzymeimmunoassay for IFN-alpha. In the assay, rIFN-alpha A was measured from approximately 100 U/ml to 1,000 U/ml, but the sensitivity and the extent to measurement were different among using monoclonal antibodies. Protease or heat denatured IFN-alpha could not be detected in the enzymeimmunoassay and thus only a biologically active form of IFN-alpha was measurable. The reproducibility of the enzymeimmunoassay was considerably high (variation coefficient was lower than 10%) and the correlation of IFN-alpha titers with CPE method was observed slightly. Although the same CPE titers, natural IFN-alpha was detected only 20% compared with rIFN-alpha A in the enzymeimmunoassay, so the assay system seemed to be very specific for rIFN-alpha A. From this observation, it was suggested that the monoclonal antibodies used in the enzymeimmunoassay should recognize a epitope specifically existed on the rIFN-alpha A molecule.