Therapeutic blockade of transforming growth factor beta fails to promote clearance of a persistent viral infection

J Virol. 2012 Jul;86(13):7060-71. doi: 10.1128/JVI.00164-12. Epub 2012 May 2.

Abstract

Persistent viral infections often overburden the immune system and are a major cause of disease in humans. During many persistent infections, antiviral T cells are maintained in a state of immune exhaustion characterized by diminished effector and helper functions. In mammalian systems, an extensive immune regulatory network exists to limit unwanted, potentially fatal immunopathology by inducing T cell exhaustion. However, this regulatory network at times overprotects the host and fosters viral persistence by severely dampening adaptive immune responsiveness. Importantly, recent studies have shown that T cell exhaustion is mediated in part by host immunoregulatory pathways (e.g., programmed death 1 [PD-1], interleukin 10 [IL-10]) and that therapeutic blockade of these pathways either before or during persistent infection can promote viral clearance. Transforming growth factor beta (TGF-β) is another immunosuppressive cytokine known to impede both self- and tumor-specific T cells, but its role in regulating antiviral immunity is not entirely understood. In this study, we inhibited TGF-β with three potent antagonists to determine whether neutralization of this regulatory molecule is a viable approach to control a persistent viral infection. Our results revealed that these inhibitors modestly elevate the number of antiviral T cells following infection with a persistent variant of lymphocytic choriomeningitis virus (LCMV) but have no impact on viral clearance. These data suggest that therapeutic neutralization of TGF-β is not an efficacious means to promote clearance of a persistent viral infection.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arenaviridae Infections / drug therapy*
  • Arenaviridae Infections / immunology*
  • Arenaviridae Infections / virology
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology*
  • Chronic Disease
  • Cytokines / biosynthesis
  • Disease Models, Animal
  • Immunologic Factors / administration & dosage*
  • Lymphocytic choriomeningitis virus / immunology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Transforming Growth Factor beta / antagonists & inhibitors*
  • Treatment Outcome

Substances

  • Cytokines
  • Immunologic Factors
  • Transforming Growth Factor beta