Immunoglobulin display vectors

1. A method for identifying recombinant cells expressing a cell surface immunoglobulin comprising:

transfecting eukaryotic host cells with an expression vector comprising in a 5′ to 3′ direction:

a promoter;

a first exon encoding an immunoglobulin heavy chain variable domain;

a second exon encoding an immunoglobulin CH1 domain;

a third exon encoding an immunoglobulin hinge domain;

a fourth exon encoding an immunoglobulin CH2 domain;

a fifth exon encoding a first immunoglobulin heavy chain CH3 domain and a cell surface tether domain;

a sixth exon encoding a second immunoglobulin heavy chain CH3 domain, wherein the polynucleotide sequence encoding said second immunoglobulin CH3 domain is identical to the polynucleotide sequence encoding said first immunoglobulin heavy chain CH3 domain;

a CH2 splice donor site located adjacent to the 3′ end of said fourth exon encoding the immunoglobulin CH2;

a CH3-TM splice acceptor site located adjacent to the 5′ end of said fifth exon encoding the immunoglobulin heavy chain CH3 domain and a cell surface tether domain;

a CH3 splice acceptor site located adjacent to the 5′ end of said sixth exon encoding the second immunoglobulin heavy chain CH3 domain;

wherein said CH2 splice donor site splices alternatively to:

said CH3-TM splice acceptor site to form a first spliced transcript, for producing a membrane-bound immunoglobulin; or

said CH3 splice acceptor site to form a second spliced transcript, for producing a secreted immunoglobulin;

and selecting recombinant cells that specifically bind a target antigen.

2. The method of claim 1 , wherein said recombinant cells are selected for target antigen binding using florescence-activated or bead-based sorting.

3. The method of claim 1 , wherein said eukaryotic host cells are selected from the group consisting of CHO, NS0, COS, 293-HEK, Jurkat, Raji, Daudi, CV-1, PerC6, SP2.0, and HeLa cells.

4. The method of claim 1 , wherein said vector further comprises an IRES element and a polynucleotide encoding a heterologous marker protein.

5. The method of claim 4 , wherein said IRES element and said polynucleotide encoding a heterologous marker protein are located downstream of said sixth exon.

6. The method of claim 4 , wherein said polynucleotide encoding a heterologous marker protein and said IRES element are located upstream of said first exon and downstream of said promoter.

7. The method of claim 1 , wherein said cell surface tether domain is selected from the group consisting of platelet derived growth factor receptor (PDGF-R) transmembrane domain, B7-1 transmembrane domain, asialoglycoprotein receptor (ASGPR) transmembrane domain and glycosidylphosphatidylinositol (GPI) signal domain.

8. The method of claim 1 , wherein said vector further comprises a second promoter operatively linked to a polynucleotide sequence encoding an immunoglobulin light chain variable domain and a polynucleotide sequence encoding an immunoglobulin light chain constant domain.

9. The method of claim 1 , wherein said CH3-TM splice acceptor site comprises the sequence SBSBGBSSSBACAG (SEQ ID NO: 1), wherein B is either G, T, or C, and S is either G or C.

10. The method of claim 1 , wherein said vector further comprises a first recombinase site located upstream of the polynucleotide sequences which encode the immunoglobulin heavy chain constant and variable domains and a second recombinase site located downstream of the polynucleotide sequence which encodes the second immunoglobulin heavy chain CH3 domain.

11. The method of claim 1 , wherein said promoter is the cytomegalovirus (CMV) promoter.

12. The method of claim 1 , wherein said vector further comprises an Epstein-Barr virus replication origin (OriP).

13. The method of claim 1 , wherein said vector further comprises a polynucleotide sequence encoding an Epstein-Barr Nuclear Antigen 1 (EBNA-1) protein.

14. The method of claim 1 , wherein said vector further comprises a drug resistance gene selected from the group consisting of a puromycin resistance gene, a neomycin resistance gene, a hygromycin gene, a xanthine-guanine phosphoribosyltransferase gene (gpt), a zeocin resistance gene, and a blasticidin resistance gene.

15. The method of claim 1 , wherein said vector further comprises a prokaryotic origin of replication.