Prevention of cytotoxic T lymphocyte responses to factor IX-expressing hepatocytes by gene transfer-induced regulatory T cells

Proc Natl Acad Sci U S A. 2006 Mar 21;103(12):4592-7. doi: 10.1073/pnas.0508685103. Epub 2006 Mar 10.


Treatment of genetic disease such as the bleeding disorder hemophilia B [deficiency in blood coagulation factor IX (F.IX)] by gene replacement therapy is hampered by the risk of immune responses to the therapeutic gene product and to the gene transfer vector. Immune competent mice of two different strains were tolerized to human F.IX by hepatic gene transfer mediated by adenoassociated viral vector. These animals were subsequently challenged by systemic administration of an E1/E3-deleted adenoviral vector, which is known to induce a cytotoxic T lymphocyte response to the transgene product. Immune tolerance prevented cytotoxic T lymphocyte activation to F.IX and CD8(+) cellular infiltrates in the liver. Moreover, a sustained and substantial increase in hepatic F.IX expression from the adenoviral vector was achieved despite in vitro T cell responses to adenoviral antigens. Cytolytic responses to therapeutic and to viral vector-derived antigens had been prevented in vivo by activation of regulatory CD4(+) T cells, which mediated suppression of inflammatory lymphocyte responses to the liver. This result suggests that augmentation of regulatory T cell activation should provide new means to avoid destructive immune responses in gene transfer.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenoviridae / genetics
  • Adoptive Transfer
  • Animals
  • Cytotoxicity, Immunologic / genetics
  • Factor IX / genetics*
  • Factor IX / immunology*
  • Factor IX / metabolism
  • Gene Transfer Techniques
  • Genetic Therapy / methods*
  • Genetic Vectors / genetics
  • Hepatocytes / immunology*
  • Hepatocytes / metabolism
  • Immune Tolerance
  • Immunosuppression Therapy / methods*
  • Male
  • Mice
  • Mice, Inbred Strains
  • T-Lymphocytes, Cytotoxic / immunology*
  • T-Lymphocytes, Regulatory / immunology


  • Factor IX