Phage display by co-translational translocation fusion polypeptide.

Method filamentous phage display, which are expressed in phage particles polypeptides of interest encoded by a DNA library, wherein said DNA library is a cDNA library or combinatorial DNA library that encodes a peptide library, one antibody library or a library based on alternative scaffolds, and wherein the polypeptides of interest are cotranslationally translocated across the cytoplasmic membrane of Gram-negative bacteria.