Research

Performance of AAV8 vectors expressing human factor IX from a hepatic-selective promoter following intravenous injection into rats

Tracey Graham , Jenny McIntosh² , Lorraine M Work¹ , Amit Nathwani² and Andrew H Baker¹

¹  British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow G12 8TA, UK

²  Department of Haematology, University College London, London, UK

author email corresponding author email

Genetic Vaccines and Therapy 2008, 6:9doi:10.1186/1479-0556-6-9

Published:	3 March 2008

Abstract

Background

Vectors based on adeno-associated virus-8 (AAV8) have shown efficiency and efficacy for liver-directed gene therapy protocols following intravascular injection, particularly in relation to haemophilia gene therapy. AAV8 has also been proposed for gene therapy targeted at skeletal and cardiac muscle, again via intravascular injection. It is important to assess vector targeting at the level of virion accumulation and transgene expression in multiple species to ascertain potential issues relating to species variation in infectivity profiles.

Methods

We used AAV8 vectors expressing human factor IX (FIX) from the liver-specific LP-1 promoter and administered this virus via the intravascular route of injection into 12 week old Wistar Kyoto rats. We assessed FIX levels in serum by ELISA and transgene expression at sacrifice by immunohistochemistry using anti-FIX antibodies. Vector DNA levels in organs we determined by real time PCR.

Results

Administration of 1 × 10¹¹ or 5 × 10¹¹ scAAV8-LP1-hFIX vector particles/rat resulted in efficient production of physiological hFIX levels, respectively in blood assessed 4 weeks post-injection. This was maintained for the 4 month duration of the study. At 4 months we observed liver persistence of vector with minimal non-hepatic distribution.

Conclusion

Our results demonstrate that AAV8 is a robust vector for delivering therapeutic genes into rat liver following intravascular injection.