The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 01, 1998
Filed:
Oct. 08, 1992
Anthony F Purchio, Seattle, WA (US);
Larry Gentry, Maumee, OH (US);
Daniel Twardzik, Bainbridge Island, WA (US);
Amy M Brunner, Seattle, WA (US);
Bristol-Myers Squibb Pharmaceutical Research Institute-Seattle, Seattle, WA (US);
Abstract
Recombinant transforming growth factor-.beta.1 (TGF-.beta.1) is expressed to high levels in Chinese hamster ovary (CHO) cells using dihydrofolate reductase (dhfr) gene amplification. The expression plasmid was derived from the pSV2 vectors and contained, in tandem, the simian TGF-.beta.1 and mouse dhfr cDNAs. Transcription of both cDNAs was controlled by the SV40 early promoter. Stepwise selection of transfected CHO cells in increasing concentrations of methotrexate yielded cell lines expressing amplified TGF-.beta.1 nucleic acid sequences. The expression plasmid DNA was amplified greater than 35-fold in one of the methotrexate selected transfectants. The major proteins secreted by these cells consisted of latent TGF-.beta.1 and TGF-.beta.1 precursor polypeptides as judged by immunoblots using site-specific anti-peptide antibodies derived from various regions of the TGF-.beta.1 precursor. Levels of recombinant TGF-.beta.1 protein secreted by these cells approached 30 ug/24 hour/10.sup.7 cells. Expression vectors encoding TGF-.beta.1 precursor variants which direct the synthesis and secretion of TGF-.beta.1 in transfected mammalian cells are also described.