A strategy for adenovirus vector targeting with a secreted single chain antibody.
BACKGROUND
Successful gene therapy will require targeted delivery vectors capable of self-directed localization. In this regard, the use of antibodies or single chain antibody fragments (scFv) in conjunction with adenovirus (Ad) vectors remains an attractive means to achieve cell-specific targeting. However, a longstanding barrier to the development of Ad vectors with genetically incorporated scFvs has been the biosynthetic incompatibility between Ad capsid proteins and antibody-derived species. Specifically, scFv require posttranslational modifications not available to Ad capsid proteins due to their cytoplasmic routing during protein synthesis and virion assembly.


RESULTS
We have therefore sought to develop scFv-targeted Ad vectors using a secreted scFv that undergoes the requisite posttranslational modifications and is trafficked for secretion. Formation of the scFv-targeted Ad vector is achieved via highly specific association of the Ad virion and a targeting scFv employing synthetic leucine zipper-like dimerization domains (zippers) that have been optimized for structural compatibility with the Ad capsid and for association with the secreted scFv. Our results show that zipper-containing Ad fiber molecules trimerize and incorporate into mature virions and that zippers can be genetically fused to scFv without ablating target recognition. Most importantly, we show that zipper-tagged virions and scFv provide target-specific gene transfer.


CONCLUSIONS
This work describes a new approach to produce targeted Ad vectors using a secreted scFv molecule, thereby avoiding the problem of structural and biosynthetic incompatibility between Ad and a complex targeting ligand. This approach may facilitate Ad targeting using a wide variety of targeting ligands directed towards a variety of cellular receptors.
Glasgow
Joel N
JN
Division of Cardiovascular Disease, Departments of Medicine, Obstetrics and Gynecology, Pathology, Surgery, and the Gene Therapy Center, University of Alabama at Birmingham, Birmingham, Alabama, USA. jng@uab.edu
Mikheeva
Galina
G
Krasnykh
Victor
V
Curiel
David T
DT
D000256:Adenoviridae / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D000595:Amino Acid Sequence; D002213:Capsid / Q000378:metabolism; D002460:Cell Line; D000939:Epitopes / Q000276:immunology; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000235:genetics*; D006801:Humans; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D057127:Single-Chain Antibodies / Q000737:chemistry / Q000378:metabolism*
D000939:Epitopes; D010455:Peptides; D011993:Recombinant Fusion Proteins; D057127:Single-Chain Antibodies