Patent ID: 7858559

Claim:
A method of selecting polynucleotides which encode an antigen-specific human immunoglobulin molecule, comprising: (a) introducing into a population of mammalian host cells capable of expressing said immunoglobulin molecule and permissive for vaccinia virus infectivity, 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 selected from the group consisting of a heavy chain variable region and a light chain variable region, wherein said variable region corresponds 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 vaccinia virus vector, provided said first library is not constructed by traditional homologous recombination; (b) introducing into said host cells 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 selected from the group consisting of a heavy chain variable region and a light chain variable region, wherein said variable region corresponds 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 said second immunoglobulin subunit polypeptide is capable of combining with said first immunoglobulin subunit polypeptide to form an immunoglobulin molecule, and wherein said second library is constructed in a vaccinia virus vector, provided said second library is not constructed by traditional homologous recombination; (c) permitting expression of immunoglobulin molecules, from said host cells; (d) contacting said immunoglobulin molecules with an antigen and detecting specific antigen-antibody complexes; and (e) recovering vaccinia virus vectors containing polynucleotides of said first library which encode immunoglobulin subunit polypeptides which, as part of an immunoglobulin molecule, are specific for said antigen.