Immunoglobulin display vectors

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.