A new subtraction technique for molecular cloning of rare antiviral antibody specificities from phage display libraries

The preparation of random combinatorial libraries exposed on the surface of phage provides a route for the selection of diverse high affinity human monoclonal antibodies. However, in particular settings, the isolation of genes coding for a rare antibody can be elusive because some epitopes are predominant and because, in the case of impure antigens, the protein or any compound of interest can be present in relatively minimal amount. In this paper, we describe the successful utilization of a new strategy of 'preadsorption' panning that allowed us to clone a rare human monoclonal antibody fragment and to access a different antibody repertoire. The procedure is easy, fast, inexpensive, can be used together with other panning techniques and can be particularly useful in cloning antibodies against rare or unknown determinants.