Production, Purification, and Characterization of Rat Interferon from Transformed Rat Cells

This chapter describes work on the production, purification, and characterization of rat interferon produced in the cultures of a continuous cell line of embryonic origin. Despite the numerous reports on interferons produced in human and a mouse system, little is known about interferon of rat origin. There are several reports, which indicate that certain subtypes of human and mouse interferon are antigenetically related to each other and that antisera raised against these subtypes can cross-react in neutralization reactions. The same cross-reactivity is found between human interferon α2 (Hu-IFN-α2 prepared in E. coli) and rat interferons, produced from Ratec cells or an alpha subtype produced in E. coli. While recombinant rat interferon α1 (rR-IFN-α1) can be neutralized with an antibody preparation directed against human interferon alpha 2 (Hu-IFN-α2), the natural resistance interferon (nR-IFN) activity is only marginally affected. In an attempt to isolate the recombinant and naturally derived rat interferons by affinity chromatography on an anti-Hu-IFN-α2 antibody column, the immunoglobulin G (IgG) fraction from antiserum directed against Hu-IFN-α2 is purified and coupled to cyanogen bromide (CNBr)-Sepharose. For that purpose, the crude serum (20 ml) is fractionated by the addition of one volume saturated ammonium sulfate.