Filamentous fusion phage cloning vectors for the study of epitopes and design of vaccines.

Foreign sequences can be inserted within the minor coat protein, pIII, of filamentous phage, creating a fusion protein that is incorporated into the virion; the virions, which we call "fusion phage," display the foreign amino acids encoded in the insert on their surface. Phage bearing specific antigenic determinants from a target gene can be purified in infectious form from a vast excess of phage bearing other determinants by affinity to antibody directed against the gene product. Fusion phage can be used as a source of antigen as a carrier-hapten conjugate for obtaining immunological reagents in rabbits, and for B epitope mapping. By generating a fusion phage library expressing virtually all possible short, amino acid sequences, it may be possible to study epitopes on immunologically important proteins without the use of synthetic peptides and without ever having cloned the genes.