TGF-beta and IL-10 production by HIV-specific CD8+ T cells is regulated by CTLA-4 signaling on CD4+ T cells

PLoS One. 2009 Dec 14;4(12):e8194. doi: 10.1371/journal.pone.0008194.

Abstract

Immune dysregulation in HIV-1 infection is associated with increased expression of inhibitory molecules such as CTLA-4, TGF-beta, and IL-10. In this study we examined one potential mechanism for regulating TGF-beta and IL-10 expression by HIV-specific suppressor CD8+ T cells. No overlap between TGF-beta, IL-10, and IFN-gamma cytokine production by HIV-specific CD8+ T cells was observed. TGF-beta positive and IL-10 positive cells were FOXP3 negative, CD25 negative, and displayed a heterogeneous surface expression of CD127. TGF-beta and IL-10 positive CD8+ T cells did not express CTLA-4. Nevertheless, CTLA-4 blockade resulted in a significant decrease in HIV-specific TGF-beta positive and IL-10 positive CD8+ T cell responses, and a concomitant increase in HIV-specific IFN-gamma positive CD8+ T cell responses. Depletion of CD4+ T cells abrogated the impact of CTLA-4 on HIV-specific TGF-beta positive and IL-10 positive CD8+ T cells. Our study suggests that CTLA-4 Signaling on CD4+ T cells regulates the inhibitory functions of the HIV-specific suppressor CD8+ T cells.

Publication types

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

MeSH terms

  • Antigens, CD / immunology*
  • CD4-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / virology*
  • CTLA-4 Antigen
  • HIV-1 / immunology*
  • Humans
  • Immunophenotyping
  • Interferon-gamma / biosynthesis
  • Interleukin-10 / biosynthesis*
  • Receptors, Transforming Growth Factor beta
  • Signal Transduction / immunology
  • Species Specificity
  • Transforming Growth Factor beta / biosynthesis*

Substances

  • Antigens, CD
  • CTLA-4 Antigen
  • CTLA4 protein, human
  • Receptors, Transforming Growth Factor beta
  • Transforming Growth Factor beta
  • Interleukin-10
  • Interferon-gamma