Immunologic differentiation between E. coli and CHO cell-derived recombinant and natural human beta-interferons.

The products of the human IFN-beta gene expressed in E. coli, Chinese hamster ovary (CHO) cells, and human fibroblasts appear similar when purified on a monoclonal antibody column and analyzed by reverse-phase HPLC, indicating little difference in their hydrophobic nature. SDS-PAGE differentiates E. coli-rHuIFN-beta ser (Mr = 17,000) from CHO-rHuIFN-beta and HuIFN-beta (Mr = 23,000), with glycosylation accounting for 26% of the apparent m.w. of the latter two proteins. CHO-rHuIFN-beta is preferentially neutralized by mouse monoclonal and monospecific rabbit polyclonal anti-HuIFN-beta antibodies, whereas E. coli-rHuIFN-beta ser is preferentially neutralized by goat polyclonal anti-E. coli-rHuIFN-beta antibodies. Adsorption measurements by a sensitive radioimmunoassay indicate that the binding of the three proteins to anti-HuIFN-beta antibodies is similar. The results show that all three molecules can be differentiated by the heteroclitic cross-reactivities of anti-HuIFN-beta and anti-E. coli-rHuIFN-beta antibodies to the antigens.