Construction of a Large Semi-synthetic Human Phage Antibody Display Library

IGEN, Inc. proposes to construct a library of functional binding domains, encompassing a vast repertoire of binding specificities, for display on the surface of bacteriophage. The displayed domains can be selected against a variety of antigens to allow the rapid isolation of monospecific binding reagents for use in immunological based detection assays. This approach provides significant time and cost savingscompared to existing methods such as hybridoma technology, since it requires no immunization or tissue culture. The Phase I effort will concentrate on the library construction, which involves cloning a complete repertoire of human antibody variable domains as a fusion with a gene encoding a bacteriophage coat protein, gIII. Fusion to gIII allows the display of the functional binding domains on the bacteriophage surface. A randomization strategy, specifically targeted to amino acids within VH CDR3, will be used to further increase the binding potential of the library. Initially, the library of domains will be selected against a variety of different test antigens to assess functionality in terms of antibody affinities, specificities and diversity. In Phase II the library will be applied to the isolation of binding reagents to targets of military interest such as pathogenic threat agents and toxins. Once constructed the phage antibody display library provides a ready and easily accessible source of specific binding reagents to virtually any antigen. The substanially reduced time for isolating the binding reagents compared to hybridomas translates into numerous potential applications, both military and civilian. These applications include development of detection reagents for biological or chemical threat agents, environmental pollutants, drug discovery and clinical immunoassays.