title: Screening phage display libraries for organ-specific vascular immunotargeting in vivo.
abstract: The molecular diversity of the luminal endothelial cell surface arising in vivo from local variations in genetic expression and tissue microenvironment may create opportunities for achieving targeted molecular imaging and therapies. Here, we describe a strategy to identify probes and their cognate antigens for targeting vascular endothelia of specific organs in vivo. We differentially screen phage libraries to select organ-targeting antibodies by using luminal endothelial cell plasma membranes isolated directly from tissue and highly enriched in natively expressed proteins exposed to the bloodstream. To obviate liver uptake of intravenously injected phage, we convert the phage-displayed antibodies into scFv-Fc fusion proteins, which then are able to rapidly target select organ(s) in vivo as visualized directly by gamma-scintigraphic whole-body imaging. Mass spectrometry helps identify the antigen targets. This comprehensive strategy provides new promise for harnessing the power of phage display for mapping vascular endothelia natively in tissue and for achieving vascular targeting of specific tissues in vivo.
authors.affiliation: Sidney Kimmel Cancer Center, 10835 Road to the Cure, San Diego, CA 92121, USA.
authors.forename: Philippe
authors.initials: P
authors.lastname: Valadon
authors.forename: Jeff D
authors.initials: JD
authors.lastname: Garnett
authors.forename: Jacqueline E
authors.initials: JE
authors.lastname: Testa
authors.forename: Marc
authors.initials: M
authors.lastname: Bauerle
authors.forename: Phil
authors.initials: P
authors.lastname: Oh
authors.forename: Jan E
authors.initials: JE
authors.lastname: Schnitzer
mesh_terms: D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000276:immunology; D000818:Animals; D000906:Antibodies / Q000032:analysis* / Q000276:immunology*; D000941:Antigens / Q000276:immunology; D042783:Endothelial Cells / Q000276:immunology* / Q000378:metabolism; D008168:Lung / Q000098:blood supply / Q000276:immunology; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009928:Organ Specificity; D019151:Peptide Library; D051381:Rats; D015203:Reproducibility of Results
chemical_list: D000906:Antibodies; D000941:Antigens; D008565:Membrane Proteins; D019151:Peptide Library; D000626:Aminopeptidases; C022750:X-Pro aminopeptidase