Abstract: The present invention provides in vitro methods of differentiating brain mural cells and methods of use, including use in blood brain barrier models. Suitable in vitro derived cell populations of brain mural cells are also provided.

Abstract: A method of creating a multicellular blood-brain barrier model is disclosed. In one embodiment, the method comprises culturing primary brain microvascular endothelial cells or embryonic stem cell-derived endothelial cells upon a permeable support in the presence of neural progenitor cells.

Abstract: This invention provides antibodies that bind brain endothelial cell receptors resulting in endocytosis/transcytosis of the receptor and bound ligands. In some embodiments, the ligand comprises the antibody in combination with a pharmaceutically active compound and the antibody directs delivery of the compound across the blood brain barrier (BBB). The invention also provides methods of identifying endothelial cell specific antibodies by panning the library against cultured cell monolayers. The invention further allows for identifying endothelial cell receptors that bind the antibody thereby providing target receptors against which to isolate further cognate ligands and their associated transport systems and by which to identify transcytosis transporters targeted by the antibodies.

Abstract: The present invention provides a genetic method for tethering polypeptides to the yeast cell wall in a form accessible for binding to macromolecules. Combining this method with fluorescence-activated cell sorting provides a means of selecting proteins with increased or decreased affinity for another molecule, altered specificity, or conditional binding. Also provided is a method for genetic fusion of the N terminus of a polypeptide of interest to the C-terminus of the yeast Aga2p cell wall protein. Attaching an scFv antibody fragment to the Aga2p agglutinin effectively mimics the cell surface display of antibodies by B cells in the immune system for affinity maturation in vivo. T cell receptor mutants can be isolated by this method that are efficiently displayed on the yeast cell surface, providing a means of altering T cell receptor binding affinity and specificity by library screening.