Claims for Patent: 7,906,327

Summary for Patent: 7,906,327

Title:	Dual expression vector system for antibody expression in bacterial and mammalian cells
Abstract:	The present invention provides a dual expression vector, and methods for its use, for the expression and secretion of a full-length polypeptide of interest in eukaryotic cells, and a soluble domain or fragment of the polypeptide in bacteria. When expressed in bacteria, transcription from a bacterial promoter within a first intron and termination at the stop codon in a second intron results in expression of a fragment of the polypeptide, e.g., a Fab fragment, whereas in mammalian cells, splicing removes the bacterial regulatory sequences located in the two introns and generates the mammalian signal sequence, allowing expression of the full-length polypeptide, e.g., IgG heavy or light chain polypeptide. The dual expression vector system of the invention can be used to select and screen for new monoclonal antibodies, as well as to optimize monoclonal antibodies for binding to antigenic molecules of interest.
Inventor(s):	Johnson; Leslie Sydnor (Darnestown, MD), Huang; Ling (Gaithersburg, MD)
Assignee:	MacroGenics, inc. (Rockville, MD)
Application Number:	11/503,399
Patent Claims:	1. A vector for expression of a heavy chain or light chain of an IgG in mammalian cells and a Fab fragment portion of a heavy chain or light chain in E. coli, said vector comprising: (a) a bacterial origin of replication; (b) a mammalian promoter and/or enhancer sequence; and (c) a nucleotide sequence encoding said heavy chain or said light chain; said nucleotide sequence comprising: (i) a mammalian signal sequence comprising a first intron, said first intron comprising a bacterial promoter and a bacterial signal sequence operatively associated with a sequence encoding the Fab domain of said heavy chain or said light chain, such that said bacterial promoter and bacterial signal sequence direct expression and secretion into the periplasmic space of said Fab domain of said heavy chain or said light chain in a bacterial cell and said mammalian promoter and said mammalian signal sequence directs expression and secretion of said heavy chain or said light chain in a mammalian cell; and (ii) when said vector encodes said heavy chain, a second intron between the CH1 and the hinge region of said heavy chain sequence, said second intron comprising a stop codon, wherein said promoter for expression in mammalian cells is operatively associated with said nucleotide sequence encoding said heavy chain or said light chain. 2. The vector of claim 1, wherein said bacterial promoter comprises a lacPO sequence. 3. The vector of claim 1, wherein said heavy chain or said light chain is a human heavy chain or light chain sequence or humanized heavy chain or light chain sequence. 4. The vector of claim 1, wherein said heavy chain or said light chain is a chimeric heavy chain or light chain sequence. 5. The vector of claim 1, wherein said bacterial signal sequence is a pelB signal sequence. 6. The vector of claim 1, wherein said promoter for expression in mammalian cells is a CMV promoter. 7. The vector of claim 1, wherein said vector encodes both heavy and light chains. 8. The vector of claim 1, wherein said light chain sequence is genetically modified to comprise a sequence encoding an epitope tag or affinity label. 9. The vector of claim 8, wherein the epitope tag is an HSV tag at the C-terminal of the Fd chain. 10. The vector of claim 8, wherein the affinity tag label is a hexahistidine tag at the C-terminal of Fd chain. 11. A bacterial cell comprising the vector of claim 1. 12. The bacterial cell of claim 11 which is an E. coli cell. 13. A mammalian cell comprising the vector of claim 1. 14. The mammalian cell of claim 13 which is a human cell or a murine cell. 15. The mammalian cell of claim 13 which is a myeloma cell, a CHO cell, or a HEK cell. 16. The cell of claim 11, wherein the vector comprises a nucleotide sequence for both heavy and light chains. 17. A cell which expresses a heavy chain and comprises the vector of claim 1, which vector comprises a light chain nucleotide sequence. 18. A cell which expresses a light chain and comprises the vector of claim 1, which vector comprises a heavy chain nucleotide sequence. 19. The vector of claim 1, wherein sequences encoding an fd (VH CH1) segment of IgG are operatively linked to sequences encoding an fd phage gene VIII protein such that, when the vector is expressed in bacterial cells, an fd phage gene VIII fusion is produced. 20. The vector of claim 1, wherein sequences encoding an fd (VH CH1) segment of IgG are operatively linked to sequences encoding an fd phage gene III protein such that, when the vector is expressed in bacterial cells, an fd gene III fusion is produced. 21. The vector of claim 8, wherein the epitope tag is a polyhistidine tag, myc tag, FLAG tag, hemagglutinin tag, a Strep tag peptide or bluetongue virus VP7 protein. 22. The vector of claim 1, wherein said vector is not designed to exist in the mammalian host cells as episomes.

Details for Patent 7,906,327

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Merck Sharp & Dohme Corp.	INTRON A	interferon alfa-2b	For Injection	103132	06/04/1986		2039-02-26
Merck Sharp & Dohme Corp.	INTRON A	interferon alfa-2b	For Injection	103132			2039-02-26
Merck Sharp & Dohme Corp.	INTRON A	interferon alfa-2b	Injection	103132			2039-02-26