Screening of phage displayed peptides without clearing of the cell culture

Abstract

This invention provides methods for screening populations of phage-displayed polypeptides that are particularly well-suited for high-throughput screening. The methods do not require the clearing of cells from a culture used to obtain the population of phage or other replicable genetic packages. Accordingly, the invention provides methods for forming complexes between a replicable genetic package displaying a polypeptide fusion and a target molecule in an uncleared cell culture containing replicable genetic package. Compositions made up of an uncleared cell culture containing replicable genetic packages displaying a polypeptide fusion and a target molecule are provided in the invention as well.

1 - 19 . (canceled)  
     
     
         20 . An uncleared cell culture comprising: 
 (a) a population of replicable genetic packages, each of which displays on its surface a fusion protein that comprises a surface-displayed replicable genetic package polypeptide and an exogenous polypeptide;    (b) a complex that comprises a target molecule and one or more members of the population of replicable genetic packages that specifically bind to said target molecule via said exogenous polypeptide; and    (c) cells in which the replicable genetic packages were amplified prior to contact with the target molecule.    
     
     
         21 . The uncleared cell culture of  claim 20 , wherein said replicable genetic packages are selected from the group consisting of bacteriophage and eukaryotic viruses.  
     
     
         22 . The uncleared cell culture of  claim 20 , wherein said target molecule is immobilized on a solid support.  
     
     
         23 . The uncleared cell culture of  claim 22 , wherein said solid support is selected from the group consisting of: a bead, a chip, a microtiter plate, a prokaryotic cell and a eukaryotic cell.  
     
     
         24 . The uncleared cell culture of  claim 20 , wherein said target molecule is selected from the group consisting of: a polypeptide, a nucleic acid, an RNA, a DNA, a small organic molecule, and a carbohydrate.  
     
     
         25 . The uncleared cell culture of  claim 20 , wherein said exogenous polypeptide is an antibody.  
     
     
         26 . The uncleared cell culture of  claim 25 , wherein said antibody is a scFv or a Fab.  
     
     
         27 . The uncleared cell culture of  claim 20 , wherein the uncleared cell culture further comprises a detection reagent that specifically binds to the replicable genetic packages.