Binding of Adeno-associated Virus Type 5 to 2,3-Linked Sialic Acid Is Required for Gene Transfer

Robert W Walters,Su Min P Yi,Shaf Keshavjee,Kevin E Brown,Michael J Welsh,John A Chiorini,Joseph Zabner

doi:10.1074/jbc.m101559200

Abstract

Recombinant adeno-associated viruses (AAV) are promising gene therapy vectors. Whereas AAV serotype 2-mediated gene transfer to muscle has partially replaced factor IX deficiency in hemophilia patients, its ability to mediate gene transfer to the lungs for cystic fibrosis is hindered by lack of apical receptors. However, AAV serotype 5 infects human airway epithelia from the lumenal surface. We found that in contrast to AAV2, the apical membrane of airway epithelia contains abundant high affinity receptors for AAV5. Binding and gene transfer with AAV5 was abolished by genetic or enzymatic removal of sialic acid from the cell surface. Furthermore, binding and gene transfer to airway epithelia was competed by lectins that specifically bind 2,3-linked sialic acid. These observations suggest that 2,3-linked sialic acid is either a receptor for AAV5 or it is a necessary component of a receptor complex. Further elucidation of the receptor for this virus should enhance understanding of parvovirus biology and expand the therapeutic targets for AAV vectors.

Highlights

Recombinant adeno-associated viruses (AAV) are promising gene therapy vectors
We found that AAV5 was 50 times more efficient than AAV2 at gene transfer from the apical surface of human airway epithelia in vitro, and it was 20 times more efficient than AAV2 at gene transfer to the murine airway epithelia in vivo [25]
Receptor-mediated Binding of AAV5—To determine if AAV5 binds to the apical surface of differentiated human airway epithelia and to learn if binding is receptor-mediated, we asked if binding fulfills classical criteria for a receptor-mediated event

Summary

Introduction

Recombinant adeno-associated viruses (AAV) are promising gene therapy vectors. Whereas AAV serotype 2-mediated gene transfer to muscle has partially replaced factor IX deficiency in hemophilia patients, its ability to mediate gene transfer to the lungs for cystic fibrosis is hindered by lack of apical receptors. Recombinant adeno-associated viruses (AAV) have been used widely for gene transfer to a variety of cells in vitro and several organs in vivo [1,2,3,4,5,6,7]. Compared with the efficiency of AAV2 gene transfer to muscle, eye, and liver, gene transfer to human airway epithelia from the apical surface is inefficient [18, 19, 21,22,23,24,25]. Adeno-associated viruses from the other five serotypes have been cloned, and their tropism has been studied in laboratory cell lines, in differentiated human airway epithelia in vitro, and in murine tissues in vivo (9 –11, 13, 25, 31–33). AAV5 has been shown to be more efficient than AAV2 at gene transfer to the ependymal cells of the ventricles, the cerebral hemispheres, and muscle [32, 34]

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