'In vitro evolution' of ligands for HCV-specific serum antibodies

We developed a strategy to improve the properties of ligands selected from phage-displayed random peptide libraries. A site-directed mutagenesis proto col that introduces mutations and extends the size of a target sequence has been set up to generate diversity in a single or in a population of clones . The pool of mutants thus created is screened to identify variants with th e desired properties. We refer to this strategy as 'in vitro evolution' of ligands. Here we report the application of this in vitro evolution protocol to the i dentification of improved ligands for HCV-specific serum antibodies. A sing le clone or population of clones were processed to generate a secondary lib rary. Screening of these libraries with sera from HCV-infected patients ide ntified peptides with an enhanced and broadened ability to detect HCV-speci fic serum antibodies.