The regulated secretory pathway in CD4(+) T cells contributes to human immunodeficiency virus type-1 cell-to-cell spread at the virological synapse

PLoS Pathog. 2011 Sep;7(9):e1002226. doi: 10.1371/journal.ppat.1002226. Epub 2011 Sep 1.

Abstract

Direct cell-cell spread of Human Immunodeficiency Virus type-1 (HIV-1) at the virological synapse (VS) is an efficient mode of dissemination between CD4(+) T cells but the mechanisms by which HIV-1 proteins are directed towards intercellular contacts is unclear. We have used confocal microscopy and electron tomography coupled with functional virology and cell biology of primary CD4(+) T cells from normal individuals and patients with Chediak-Higashi Syndrome and report that the HIV-1 VS displays a regulated secretion phenotype that shares features with polarized secretion at the T cell immunological synapse (IS). Cell-cell contact at the VS re-orientates the microtubule organizing center (MTOC) and organelles within the HIV-1-infected T cell towards the engaged target T cell, concomitant with polarization of viral proteins. Directed secretion of proteins at the T cell IS requires specialized organelles termed secretory lysosomes (SL) and we show that the HIV-1 envelope glycoprotein (Env) localizes with CTLA-4 and FasL in SL-related compartments and at the VS. Finally, CD4(+) T cells that are disabled for regulated secretion are less able to support productive cell-to-cell HIV-1 spread. We propose that HIV-1 hijacks the regulated secretory pathway of CD4(+) T cells to enhance its dissemination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD4-Positive T-Lymphocytes / metabolism*
  • CD4-Positive T-Lymphocytes / physiology
  • CD4-Positive T-Lymphocytes / virology
  • Cells, Cultured
  • Chediak-Higashi Syndrome / physiopathology
  • Chediak-Higashi Syndrome / virology
  • HIV-1 / physiology*
  • Humans
  • Lysosomes / physiology
  • Microscopy, Confocal
  • Microtubule-Organizing Center / physiology
  • Qa-SNARE Proteins / physiology
  • Secretory Pathway
  • Synapses / physiology*
  • Viral Proteins / metabolism*
  • Virus Internalization

Substances

  • Qa-SNARE Proteins
  • Viral Proteins