Gene transfer into hepatocytes mediated by herpes simplex virus-Epstein-Barr virus hybrid amplicons

Lars Müller, Okay Saydam, Yoshinaga Saeki, Irma Heid, Cornel Fraefel

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Gene transfer into hepatocytes is highly desirable for the long-term goal of replacing deficient proteins and correcting metabolic disorders. Vectors based on herpes simplex virus type-1 (HSV-1) have been demonstrated to mediate efficient gene transfer into hepatocytes both in vitro and in vivo. Large transgene capacity and extrachromosomal persistence make HSV-1/EBV hybrid amplicon vectors an attractive candidate for hepatic gene replacement therapy. To assess liver-directed gene transfer, we constructed (i) a conventional HSV-1 amplicon vector encoding a secreted reporter protein (secreted alkaline phosphatase, SEAP) under the control of the HSV-1 immediate-early 4/5 promoter; (ii) a HSV-1 amplicon encoding SEAP under the control of the artificial CAG promoter (the chicken β-actin promoter and cytomegalovirus (CMV) immediate-early enhancer); and (iii) a HSV-1/EBV hybrid amplicon, also encoding SEAP under the control of the CAG promoter. While all three vector constructs yielded high SEAP concentrations in vitro and in vivo, use of HSV-1/EBV hybrid amplicon vectors significantly prolonged the duration of gene expression. Using conventional amplicon vectors in cultured hepatocytes, SEAP was detected for two weeks, whereas SEAP was detected for at least six weeks when HSV-1/EBV amplicons were used. Intraparenchymal injection into the liver of SICD mice yielded high (up to 77 ng of SEAP per milliliter serum) and sustained (greater than three weeks) expression of SEAP. Serum transaminases (ALT/AST) were measured at different time points to monitor for hepatocellular damage. While initially elevated four times above baseline, the transaminase levels returned to normal after three to seven days. These results demonstrate the usefulness of HSV-1-based amplicons and SEAP for the evaluation of gene replacement strategies in the liver.

Original languageEnglish (US)
Pages (from-to)65-72
Number of pages8
JournalJournal of Virological Methods
Issue number1
StatePublished - Jan 2005
Externally publishedYes

Bibliographical note

Funding Information:
We would like to thank Dr. H. Lutz for analysis of transaminase levels in serum samples and Drs. H.P. Hefti und K. Tobler for a critical reading of the manuscript. This work was supported by the Swiss National Science Foundation no. 3100-100195.

Copyright 2012 Elsevier B.V., All rights reserved.


  • Amplicon
  • Gene therapy
  • HSV-1 hybrid vectors
  • Liver
  • SEAP


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