Original Article

Gene Therapy (2010) 17, 37–49; doi:10.1038/gt.2009.118; published online 10 September 2009

Foamy combinatorial anti-HIV vectors with MGMTP140K potently inhibit HIV-1 and SHIV replication and mediate selection in vivo

H-P Kiem1,2,3, R A Wu1, G Sun4, D von Laer5, J J Rossi4 and G D Trobridge1,2

  1. 1Clinical Research Division, Fred Hutchinson Cancer Research Center, University of Washington, Seattle, WA, USA
  2. 2Department of Medicine, University of Washington, Seattle, WA, USA
  3. 3Department of Pathology, University of Washington, Seattle, WA, USA
  4. 4Department of Molecular Biology, Beckman Research Institute of City of Hope, Duarte, CA, USA
  5. 5Georg-Speyer-Haus, Institute for Biomedical Research, Frankfurt, Germany

Correspondence: Dr H-P Kiem, Clinical Research Division, Fred Hutchinson Cancer Research Center, University of Washington, 1100 Fairview Avenue North, D1-100, Seattle, WA 98109-1024, USA. E-mail: hkiem@fhcrc.org; Dr GD Trobridge, gtrobrid@fhcrc.org

Received 20 July 2009; Accepted 20 July 2009; Published online 10 September 2009.



Highly active antiretroviral therapy has greatly reduced the morbidity and mortality from human immunodeficiency virus (HIV) infection, but AIDS continues to be a serious health problem worldwide. Despite enormous efforts to develop a vaccine, there is still no cure, and alternative approaches including gene therapy should be explored. In this study we developed and compared combinatorial foamy virus (FV) anti-HIV vectors that also express a mutant methylguanine methyltransferase (MGMTP140K) transgene to increase the percentage of gene-modified cells after transplantation. These FV vectors inhibit replication of HIV-1 and also the simian immunodeficiency virus/HIV-1 (SHIV) chimera that can be used in monkey AIDS gene therapy studies. We identified a combinatorial FV vector that expresses 3 anti-HIV transgenes and inhibits viral replication by over 4 logs in a viral challenge assay. This FV anti-HIV vector expresses an HIV fusion inhibitor and two short hairpin RNAs (shRNAs) targeted to HIV-1 tat and rev, and can be produced at high titer (3.8 × 107 transducing unitsml−1) using improved helper plasmids suitable for clinical use. Using a competitive repopulation assay, we show that human CD34+ cells transduced with this combinatorial FV vector efficiently engraft in a mouse xenotransplantation model, and that the percentage of transduced repopulating cells can be increased after transplantation.


foamy vector, hematopoietic stem cell, methylguanine methyltransferase, human immunodeficiency virus (HIV), simian–human immunodeficiency virus(SHIV)