1. ¹Got-a-Gene AB, Kullavik, Sweden
2. ²Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
3. ³Department of Biotechnology, Kungl Tekniska Högskolan, Albanova University Center, Stockholm, Sweden
4. ⁴Department of Molecular Cell Biology, Leiden University Medical Centre, Leiden, The Netherlands
5. ⁵Laboratoire de Virologie et Pathogénèse Virale, Université Claude Bernard de Lyon, CNRS UMR-5537, Faculté de Médecine RTH Laennec, Lyon Cedex, France
6. ⁶Department of Surgical Oncology and Technology, Faculty of Medicine, Imperial College, Hammersmith Hospital Campus, London, UK

Correspondence: Dr L Lindholm, Got-a-Gene AB, Ö Kyviksvägen 18, SE 42930 Kullavik, Sweden. E-mail: leif.lindholm@gotagene.se

Received 28 April 2006; Revised 30 September 2006; Accepted 17 November 2006; Published online 2 February 2007.

Abstract

In order to use adenovirus (Ad) type 5 (Ad5) for cancer gene therapy, Ad needs to be de-targeted from its native receptors and re-targeted to a tumor antigen. A limiting factor for this has been to find a ligand that (i) binds a relevant target, (ii) is able to fold correctly in the reducing environment of the cytoplasm and (iii) when incorporated at an optimal position on the virion results in a virus with a low physical particle to plaque-forming units ratio to diminish the viral load to be administered to a future patient. Here, we present a solution to these problems by producing a genetically re-targeted Ad with a tandem repeat of the HER2/neu reactive Affibody molecule (ZH) in the HI-loop of a Coxsackie B virus and Ad receptor (CAR) binding ablated fiber genetically modified to contain sequences for flexible linkers between the ZH and the knob sequences. ZH is an Affibody molecule specific for the extracellular domain of human epidermal growth factor receptor 2 (HER2/neu) that is overexpressed in inter alia breast and ovarian carcinomas. The virus presented here exhibits near wild-type growth characteristics, infects cells via HER2/neu instead of CAR and represents an important step toward the development of genetically re-targeted adenoviruses with clinical relevance.