Probing the natural antibody repertoire by combinatorial cloning of IgM and IgD isotypes in phage display vectors

It is well known that immunoglobulins with no identifiable immunogenic orig in, called natural antibodies, are present in the sera of healthy individua ls and their role as a defence against important pathogens has been propose d. Unfortunately, the studies are hampered by the fact that these immunoglo bulins seem to have low affinity and to be polyreactive, and are commonly a vailable in polyclonal preparations. Lately, new technologies for the produ ction of monoclonal antibodies became available, and in particular the clon ing of genes coding for antibody fragments in combinatorial phage display v ectors provided a handy tool for the selection of human monoclonal antibodi es, in this work, we describe the successful development of a technology fo r the molecular cloning of combinatorial phage display libraries containing genes coding exclusively for antibody fragment of the IgM or IgD phenotype . These libraries can be useful for molecular cloning of monoclonal antibod ies of the IgM and IgD phenotype and can help elucidate the role played by natural antibodies in defence against infectious agents.