Identification of HCV core mimotopes: improved methods for the selection and use of disease-related phage-displayed peptides

Disease-specific epitope discovery from random peptide libraries displayed on phage using sera from patients involves a number of screening steps with many immune and non-immune sera. To rapidly identify mimotopes of the human hepatitis C virus (HCV) core protein, we have used an anti-core human monoclonal antibody (mAb; B12.F8) as a probe in screening phage that were affinity-selected using a serum from an HCV infected patient. Three different positive phage were isolated displaying low or no homology with the natural antigen, but which still efficiently bound to the antigen binding site of the B12.F8 antibody. Testing the reactivity of these phage with forty-five sera from HCV infected patients showed that antibodies recognizing them are present in more than 80% of this population. These antibodies showed distinct fine specificity, as they bound the selected phage in a mutually exclusive fashion. Co-expression of two mimotopes in the same cells led to chimeric particles which were recognized by antibodies of different specificity. These data provide novel information on the potential use of the phage display technology for the characterization of antibody specificity as well as disease diagnosis and prevention.