An interferon-alpha-induced tethering mechanism inhibits HIV-1 and Ebola virus particle release but is counteracted by the HIV-1 Vpu protein

Cell Host Microbe. 2007 Sep 13;2(3):193-203. doi: 10.1016/j.chom.2007.08.001.

Abstract

Type 1 interferon (IFN) inhibits the release of HIV-1 virus particles via poorly defined mechanisms. Here, we show that IFNalpha induces retention of viral particles on the surface of fibroblasts, T cells, or primary lymphocytes infected with HIV-1 lacking the Vpu protein. Retained particles are tethered to cell surfaces, can be endocytosed, appear fully assembled, exhibit mature morphology, and can be detached by protease. Strikingly, expression of the HIV-1 Vpu protein attenuates the ability of human cells to adhere to, and thereby retain, nascent HIV-1 particles upon IFNalpha treatment. Vpu also counteracts the IFNalpha-induced retention of virus-like particles assembled from the Ebola virus matrix protein. Furthermore, levels of IFNalpha that suppress replication of Vpu-defective HIV-1 have little effect on wild-type HIV-1. Thus, we propose that HIV-1 expresses Vpu to counteract an IFNalpha-induced, general host defense that inhibits dissemination of enveloped virions from the surface of infected cells.

Publication types

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

MeSH terms

  • Animals
  • Cell Line
  • Chlorocebus aethiops
  • Ebolavirus / growth & development*
  • Ebolavirus / immunology
  • HIV-1 / growth & development*
  • HIV-1 / immunology
  • Human Immunodeficiency Virus Proteins / genetics
  • Human Immunodeficiency Virus Proteins / physiology*
  • Humans
  • Interferon-alpha / antagonists & inhibitors*
  • Interferon-alpha / immunology*
  • Viral Regulatory and Accessory Proteins / genetics
  • Viral Regulatory and Accessory Proteins / physiology*
  • Virion / immunology

Substances

  • Human Immunodeficiency Virus Proteins
  • Interferon-alpha
  • Viral Regulatory and Accessory Proteins
  • vpu protein, Human immunodeficiency virus 1