Characterization of Antibodies Against Recombinant HuIFN-γ Produced by Hybridoma Cells

Abstract

Balbc/c mice were immunized with purified recombinant E. coli-derived human gammainterferon (HuIFN-γ). Their spleen cells were fused with a mouse myeloma cell line (Sp2/0). Hybridomas producing antibodies reacting with HuIFN-γ were screened by a soluble-phase radioimmunoassay using pure ¹²⁵I-labeled cloned IFN-γ as antigen, and tested for their ability to neutralize the antiviral activity of IFN. Three hybridomas S1-1, S1-2, and S1-3, were cloned and subcloned and remained stable. Although the antibodies produced by clones S1-1 and S1-2 were both able to neutralize specifically the antiviral activity of natural and recombinant HuIFN-γ, they appeared to recognize different epitopes on the HuIFN-γ molecule. The antibodies produced by the S1-3 clone failed to neutralize the antiviral activity of either interferon. The antibodies from all three clones were characterized as IgG1 subclass. Their affinity constants were determined from competitive inhibition curves and ranged from 1 to 4.3 × 10⁸ M^-1.