IL-7 promotes CD95-induced apoptosis in B cells via the IFN-γ/STAT1 pathway

PLoS One. 2011;6(12):e28629. doi: 10.1371/journal.pone.0028629. Epub 2011 Dec 14.

Abstract

Interleukin-7 (IL-7) concentrations are increased in the blood of CD4+ T cell depleted individuals, including HIV-1 infected patients. High IL-7 levels might stimulate T cell activation and, as we have shown earlier, IL-7 can prime resting T cell to CD95 induced apoptosis as well. HIV-1 infection leads to B cell abnormalities including increased apoptosis via the CD95 (Fas) death receptor pathway and loss of memory B cells. Peripheral B cells are not sensitive for IL-7, due to the lack of IL-7Ra expression on their surface; however, here we demonstrate that high IL-7 concentration can prime resting B cells to CD95-mediated apoptosis via an indirect mechanism. T cells cultured with IL-7 induced high CD95 expression on resting B cells together with an increased sensitivity to CD95 mediated apoptosis. As the mediator molecule responsible for B cell priming to CD95 mediated apoptosis we identified the cytokine IFN-γ that T cells secreted in high amounts in response to IL-7. These results suggest that the lymphopenia induced cytokine IL-7 can contribute to the increased B cell apoptosis observed in HIV-1 infected individuals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects*
  • B-Lymphocytes / cytology*
  • B-Lymphocytes / drug effects
  • B-Lymphocytes / metabolism*
  • Humans
  • Interferon-gamma / biosynthesis
  • Interferon-gamma / metabolism*
  • Interleukin Receptor Common gamma Subunit / metabolism
  • Interleukin-7 / pharmacology*
  • STAT1 Transcription Factor / metabolism*
  • Signal Transduction / drug effects
  • Solubility / drug effects
  • Stromal Cells / drug effects
  • Stromal Cells / metabolism
  • T-Lymphocytes / cytology
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / metabolism
  • Up-Regulation / drug effects
  • fas Receptor / metabolism*

Substances

  • FAS protein, human
  • IL7 protein, human
  • Interleukin Receptor Common gamma Subunit
  • Interleukin-7
  • STAT1 Transcription Factor
  • STAT1 protein, human
  • fas Receptor
  • Interferon-gamma