Antigenic characterization of recombinant, lymphoblastoid, and leukocyte IFN-alpha by monoclonal antibodies

To gain more insight into similarities of different interferon-alpha (IFN-a lpha) species, we evaluated neutralization and immunoactivity of a variety of IFN preparations with various monoclonal antibodies (IFN-alpha mAb), Nin e IFN-alpha mAb obtained through immunization with recombinant IFN-alpha (r mAb), lymphoblastoid IFN-alpha (LY mAb), and leukocyte IFN-alpha (LE mAb) w ere tested. The IFN-alpha mAb were evaluated for their ability to neutraliz e the antiviral activity of 11 recombinant IFN-alpha subtypes, two recombin ant IFN-alpha hybrids, and lymphoblastoid and leukocyte IFN-alpha preparati ons. The same IFN-alpha mAb were also used in immunoblotting, and some of t hem were used in immunoaffinity chromatography. The results of the neutrali zation assay reveal that the IFN-alpha mAb significantly differ in their ab ility to neutralize the individual IFN-alpha species. Interestingly, none o f the IFN-alpha mAb was able to neutralize all the IFN-cu species, In parti cular, rmAb were unable to neutralize LE-IFN-alpha or LY-IFN-alpha, whereas LE mAb and LY mAb efficiently neutralized rIFN-alpha 2. In some cases, the epitopes to which IFN-alpha mAb are directed were identified through the u se of synthetic fragments of IFN-alpha 2 or by evaluating the selectivity i n binding to IFN-alpha subtypes.