Innate and adaptive immune responses both contribute to pathological CD4 T cell activation in HIV-1 infected Ugandans

PLoS One. 2011 Apr 19;6(4):e18779. doi: 10.1371/journal.pone.0018779.

Abstract

HIV-1 disease progression is associated with persistent immune activation. However, the nature of this association is incompletely understood. Here, we investigated immune activation in the CD4 T cell compartment of chronically HIV-1 infected individuals from Rakai, Uganda. Levels of CD4 T cell activation, assessed as co-expression of PD-1, CD38 and HLA-DR, correlated directly to viral load and inversely to CD4 count. Deeper characterization of these cells indicated an effector memory phenotype with relatively frequent expression of Ki67 despite their PD-1 expression, and levels of these cells were inversely associated with FoxP3+ regulatory T cells. We therefore use the term deregulated effector memory (DEM) cells to describe them. CD4 T cells with a DEM phenotype could be generated by antigen stimulation of recall responses in vitro. Responses against HIV-1 and CMV antigens were enriched among the DEM CD4 T cells in patients, and the diverse Vβ repertoire of DEM CD4 T cells suggested they include diverse antigen-specificities. Furthermore, the levels of DEM CD4 T cells correlated directly to soluble CD14 (sCD14) and IL-6, markers of innate immune activation, in plasma. The size of the activated DEM CD4 T cell subset was predictive of the rate of disease progression, whereas IL-6 was only weakly predictive and sCD14 was not predictive. Taken together, these results are consistent with a model where systemic innate immune activation and chronic antigen stimulation of adaptive T cell responses both play important roles in driving pathological CD4 T cell immune activation in HIV-1 disease.

Publication types

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

MeSH terms

  • ADP-ribosyl Cyclase 1 / metabolism
  • Adaptive Immunity / immunology*
  • Adolescent
  • Adult
  • Antigens, CD / metabolism
  • Antigens, Viral / immunology
  • Apoptosis Regulatory Proteins / metabolism
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / pathology*
  • CD4-Positive T-Lymphocytes / virology*
  • Cell Proliferation
  • Chronic Disease
  • Disease Progression
  • Female
  • HIV Infections / blood
  • HIV Infections / immunology
  • HIV Infections / virology*
  • HIV-1 / immunology*
  • HLA-DR Antigens / metabolism
  • Humans
  • Immunity, Innate / immunology*
  • Immunologic Memory / immunology
  • Interleukin-6 / blood
  • Lipopolysaccharide Receptors / blood
  • Lymphocyte Activation / immunology*
  • Male
  • Middle Aged
  • Programmed Cell Death 1 Receptor
  • Receptors, Antigen, T-Cell, alpha-beta / metabolism
  • Uganda
  • Young Adult

Substances

  • Antigens, CD
  • Antigens, Viral
  • Apoptosis Regulatory Proteins
  • HLA-DR Antigens
  • Interleukin-6
  • Lipopolysaccharide Receptors
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor
  • Receptors, Antigen, T-Cell, alpha-beta
  • ADP-ribosyl Cyclase 1