Biological properties of human interferon beta 1 synthesized in recombinant bacteria

Human fibroblast interferon, designated IFN-beta 1, has been produced in E. coli by direct expression of the cloned cDNA coding for the mature polypeptide. Bacterial lysates from recombinant cultures contain a polypeptide with an apparent molecular weight of 17,500 that corresponds in size to the unglycosylated IFN-beta 1 molecule. The latter could be specifically immunoprecipitated by antibodies to purified natural IFN-beta and could inhibit the replication of Herpes simplex virus types 1 and 2 in many different cell lines. Like the natural fibroblast IFN-beta, the bacterial IFN-beta 1 was active in many human cell lines, less active in a monkey cell line and inactive in rabbit and mouse fibroblasts. The antibody titre required to neutralise the anti-herpes activity of both IFN preparations was similar suggesting that they have the same specific activities. Similarly, the bacterial IFN-beta 1 was equally active in inhibiting the proliferation of Daudi cells grown in culture. Bacterial IFN-beta 1 was also capable of enhancing natural killer cell activity and antibody-dependent cellular cytotoxicity in vitro. Thus, IFN-beta 1 produced in recombinant bacteria displays a large range of biological properties ascribed to the natural fibroblast IFN-beta molecule.