MONOCLONAL-ANTIBODIES AND ENZYME IMMUNOASSAYS SPECIFIC FOR HUMAN INTERFERON (IFN)-OMEGA-1 - EVIDENCE THAT IFN-OMEGA-1 IS A COMPONENT OF HUMAN-LEUKOCYTE IFN

Four hybridoma cell lines secreting monoclonal IgG antibodies to human interferon (IFN) ω1 (=IFN-αII1) were developed, using spleen cells of mice immunized with IFN-ω1 and/or a novel hybrid interferon, IFN-ω1/α2. All antibodies (OMG-2, -4, -5, and -7) neutralize the antiviral activity of IFN-w1 and show distinct patterns of reactivity with the hybrid proteins, IFN-ω1/α2 and IFN-α2c/ω1. However, none of the antibodies is able to neutralize human IFN-α, confirming earlier observations that IFN-ω1 and IFN-α are antigenically unrelated. The epitope specificities of the antibodies were further characterized in direct and competitive enzyme immunoassays (ELISAs). All binary antibody combinations were tested for their suitability for a two-site ("sandwich") ELISA for IFN-ω1, using horse radish peroxidase as the marker enzyme. A configuration employing OMG-2 for antigen capture and OMG-7 as the detector antibody resulted in the highest assay sensitivity (approximately 10 pg IFN-ω1 /ml) and was studied further. This one-step assay is highly specific for IFN-ω1 and does not recognize human IFN-α, -β and -γ, thus allowing for determination of IFN-ω1 levels in natural mixtures of human IFNs. Using this ELISA, it was found that IFN-ω1 is present in IFN preparations derived from virus-induced human peripheral blood leukocytes and may constitute as much as 15% of the total leukocyte IFN activity. IFN-ω1 was also detected at somewhat lower levels in preparations of human "lymphoblastoid" IFN. © 1990.