In Vitro methods of producing and identifying immunoglobulin molecules in eukaryotic cells

A kit for the selection of antigen-specific recombinant immunoglobulins expressed in a eukaryotic host cell comprising:

• (a) a first library of polynucleotides encoding, through operable association with a transcriptional control region, a plurality of first immunoglobulin subunit polypeptides, each first immunoglobulin subunit polypeptide comprising:
• (i) a first immunoglobulin constant region selected from the group consisting of a heavy chain constant region and a light chain constant region,
• (ii) an immunoglobulin variable region corresponding to said first constant region, and
• (iii) a signal peptide capable of directing cell surface expression or secretion of said first immunoglobulin subunit polypeptide,
• wherein said first library is constructed in a eukaryotic virus vector;
• (b) a second library of polynucleotides encoding, through operable association with a transcriptional control region, a plurality of second immunoglobulin subunit polypeptides, each comprising:
• (i) a second immunoglobulin constant region selected from the group consisting of a heavy chain constant region and a light chain constant region, wherein said second immunoglobulin constant region is not the same as said first immunoglobulin constant region,
• (ii) an immunoglobulin variable region corresponding to said second constant region, and
• (iii) a signal peptide capable of directing cell surface expression or secretion of said second immunoglobulin subunit polypeptide,
• wherein a said second immunoglobulin subunit polypeptide is capable of combining with said first immunoglobulin subunit polypeptide to form a surface immunoglobulin molecule, or antigen-specific fragment thereof, and wherein said second library is constructed in a eukaryotic virus vector;
• and
• (c) a population of host cells capable of expressing said immunoglobulin molecules;
• wherein said first and second libraries are provided both as infectious virus particles and as inactivated virus particles, and wherein said inactivated virus particles infect said host cells and allow expression of said first and second immunoglobulin subunit polypeptides, but do not undergo virus replication;
• and
• wherein antigen-specific immunoglobulin molecules expressed by said host cells are selected through interaction with an antigen.