Identification of peptide sequences that induce the transport of phage across the gastrointestinal mucosal barrier.

To investigate whether specific peptide sequences could induce virion transport across the intestinal barrier, we used phage display to both identify signalling peptides capable of inducing trans-intestinal transport and also provide a suitable model of virion translocation. We utilised simple, single-round high input in vivo biopanning protocol using a 7-mer random amino acid phage display library. Phage were applied by gavage and translocation across the intestinal barrier assessed by phage recovery from the spleen 2h later. Following isolation, a number of phage were sequenced and several homologies with HIV gp120 were identified. Immunocytochemical analysis of phage translocation across the intestinal barrier by a phage bearing the peptide YPRLLTP demonstrated that phage were actively transported along specific channels. It is concluded that utilisation of in vivo phage display (IVPD) has provided evidence for a specific peptide-guided transport of undegraded cargo across the intestinal barrier, modelled by M13 phage.