Development of a New Mammalian Cell Expression System

Period of Performance: 09/27/1989 - 03/26/1990


Phase 1 SBIR

Recipient Firm

Medimmune, Inc.
19 Firstfield Rd
Gaithersburg, MD 20878
Principal Investigator


Numerous expression systems exist for production of proteins in both prokaryotic and eukaryotic cells. Each system has its own set of advantages as well as shortcomings. This need remains for a mammalian cell expression system that can achieve high level target gene expression, correctly process proteins of mammalian origin, and is economical and easy to use. Recently, we have established a mammalian expression system capable of significant production levels of target proteins. This system is based on coinfection of cultured cells with two recombinant vaccinia viruses. One recombinant vaccinia virus provides constitutive expression of bacteriophage T7 RNA polymerase, and the second contains a T7-promoter-controlled target gene. The two virus system was required for stability reasons. We plan to use the regulatory elements of the Escherichia coli lac operator/repressor system to regulate expression of T7 RNA polymerase. If expression of T7 RNA polymerase could be controlled, a single virus expression system may be feasible. If successful, this system will be exploited as a superior means for the efficient bioproduction of mammalian proteins.