Production of monoclonal antibodies to human IFN-alpha and their use for analysis of the antigenic composition of various natural interferons.

We have established three hybridoma cell lines (designated EBI-1, -2, and -3) secreting immunoglobulin G (IgG) antibodies specific for human alpha-interferon (HuIFN-alpha) by fusing P3X63Ag8.6.5.3 myeloma cells with spleen cells of mice immunized with human "lymphoblastoid" (NC-37) interferon (IFN). The antibodies were used to study the antigenic diversity of a number of IFNs derived from blood leukocytes and lymphoid cell lines. When incubated with 10 U of IFN, EBI-1 antibodies completely neutralized the antiviral activity of HuIFN-alpha rA produced in E coli as well as of IFN produced spontaneously in several lymphoblastoid cell lines. In contrast, only 60-70% of alpha-interferon (IFN-alpha) induced in leukocytes, lymphoma, or lymphoblastoid cell lines by Sendai virus or poly (I):(C) could be neutralized by the antibody; furthermore, IFN-alpha produced spontaneously in bromodeoxyuridine-treated lymphoma cells was also only partially neutralized. EBI-2 and EBI-3 antibodies were tested against a smaller set of samples and found to react similarly. Our results indicate that human IFN-alpha subtypes can be grouped into at least two antigenically distinguishable subsets, one of which being represented by IFN-alpha A, and that these subsets can be expressed differently under different conditions in a given cell type.