Profiling the autoantibody repertoire by screening phage-displayed human cDNA libraries

The advent of the serological identification of antigens by procedures such as cDNA cloning and recombinant protein expression has allowed the direct molecular definition of immunogenic proteins. The phage-display technology provides several advantages over conventional immunoscreening procedures based on plasmid or lambda-phage cDNA libraries. So far, attempts to display open reading frames, such as those encoded by cDNA fragments, on filamentous phages have not been very successful. We managed to develop a strategy based on "folding reporters" which allows filtering out open reading frames from DNA and displaying them on filamentous phages in such a way that they are amenable to subsequent selection or screening. Once the cDNA library of interest is created, phage-display technology is used for selection of novel putative antigens; these are then validated by printing isolated protein on microarray and screening with patients' sera.