Abstract: Disclosed herein are multimeric molecular complexes and compounds that are multivalent, i.e., they have two or more targeting elements directed to a ligand that confers paracellular transporting properties and/or transcytotic properties to complexes and compounds to which it is bound. The complexes and compounds have properties that are different from the properties of monomers, complexes and compounds having only one targeting element directed to a paracellular and/or transcytotic ligand. The complexes and compounds of the invention undergo endocytosis, transcytosis and exocytosis; following endocytosis, the complexes or compounds may be transported into the cytosol or an organelle of a cell. In polarized cells, transcytosis can proceed in a “forward” or “reverse” direction. Reverse transcytosis is used for the non-invasive delivery of biologically active agents from the lumen of, e.g., the gastrointestinal tract or the airways of lungs, to the circulatory system.

Abstract: Disclosed herein are complexes and compounds that pass through cellular barriers to deliver compounds into, through and out of cells, and methods of producing and using such complexes and compounds. The complexes and compounds of the invention comprise a biologically active portion and a targeting element directed to a ligand that confers transcellular, transcytotic or paracellular transporting properties to an agent specifically bound to the ligand. Also disclosed are complexes and compounds that comprise two or more targeting elements directed to a ligand that confers transcellular, transcytotic or paracellular transporting properties to an agent specifically bound to the ligand. Preferred ligands include but are not limited to the stalk of pIgR, a pIgR domain, an amino acid sequence that is conserved among pIgR's from different animals, and one of several regions of pIgR defined herein.

Abstract: The invention provides compositions and methods for specific binding to a region of the polymeric immunoglobulin receptor (pIgR) of a cell with the provisos that the ligand does not substantially bind to the most abundant form of the secretory component (SC) of pIgR present in an organ of interest of an animal of interest under physiological conditions, and does not bind to the pIgR stalk. In some embodiments, the ligand decreases cleavage of SC from the stalk by at least one-third. The ligands and methods of the invention can be used with both birds and mammals. In more preferred embodiments, the animal is a mammal. In the most preferred embodiment, the animal is a human. The ligand may be targeted into the cell or may undergo retrograde transcytosis and release at the basolateral side of the cell, and may comprise a biologically active composition.

Abstract: Disclosed herein are multimeric molecular complexes and compounds that are multivalent, i.e., they have two or more targeting elements directed to a ligand that confers paracellular transporting properties and/or transcytotic properties to complexes and compounds to which it is bound. The complexes and compounds have properties that are different from the properties of monomers, complexes and compounds having only one targeting element directed to a paracellular and/or transcytotic ligand. The complexes and compounds of the invention undergo endocytosis, transcytosis and exocytosis; following endocytosis, the complexes or compounds may be transported into the cytosol or an organelle of a cell. In polarized cells, transcytosis can proceed in a “forward” or “reverse” direction. Reverse transcytosis is used for the non-invasive delivery of biologically active agents from the lumen of, e.g., the gastrointestinal tract or the airways of lungs, to the circulatory system.

Abstract: Disclosed herein are complexes and compounds that pass through cellular barriers to deliver compounds into, through and out of cells, and methods of producing and using such complexes and compounds. The complexes and compounds of the invention comprise a biologically active portion and a targeting element directed to a ligand that confers transcellular, transcytotic or paracellular transporting properties to an agent specifically bound to the ligand, with the proviso that the targeting element is not an antibody. Also disclosed are complexes and compounds that comprise two or more targeting elements directed to a ligand that confers transcellular, transcytotic or paracellular transporting properties to an agent specifically bound to the ligand. Preferred ligands include but are not limited to the stalk of pIgR, a pIgR domain, an amino acid sequence that is conserved among pIgR's from different animals, and one of several regions of pIgR defined herein.