Eukaryotic signal sequences for polypeptide expression and polypeptide display libraries

A method of displaying a polypeptide from a replicable genetic package, which method comprises the steps of expressing in a bacterial host cell a polypeptide display vector comprising a polynucleotide encoding the polypeptide, wherein the polynucleotide is operably linked to a eukaryotic signal sequence which encodes a signal peptide MRTLAILAAILLVALQAQA (SEQ ID NO:

• 2), whereby the polynucleotide sequence and signal sequence are expressed and secreted, and the expressed signal peptide sequence is processed from the expressed polypeptide, such that the polypeptide is displayed from the outer surface of the replicable genetic package, wherein the replicable genetic package is a bacteriophage or phagemid, and wherein the polypeptide is an antibody.