Modulation of cytokine release and gene expression by the immunosuppressive domain of gp41 of HIV-1

PLoS One. 2013;8(1):e55199. doi: 10.1371/journal.pone.0055199. Epub 2013 Jan 30.


The transmembrane envelope protein gp41 of the human immunodeficiency virus HIV-1 plays an important role during infection allowing fusion of the viral and cellular membrane. In addition, there is increasing evidence that gp41 may contribute to the immunodeficiency induced by HIV-1. Recombinant gp41 and a synthetic peptide corresponding to a highly conserved domain in gp41, the immunosuppressive (isu) domain, have been shown to inhibit mitogen-induced activation of human peripheral blood mononuclear cells (PBMCs) and to increase release of IL-6 and IL-10 from these cells. We recently reported that a single mutation in the isu domain of gp41 abrogated the immunosuppressive properties and that HIV-1 sequences containing such abrogating mutations had never been isolated from infected individuals. Here, we studied the influence of the isu peptide on the release of 66 cytokines and the expression of 27,000 genes in PBMCs. Incubation of PBMCs with isu peptide homopolymers increased the expression of 16 cytokines among them IL-6 and IL-10, and decreased that of IL-2 and CXCL9. Interestingly, the extend of cytokine modulation was donor-dependent. Among the genes up-regulated were IL-6, IL-8, IL-10 but also MMP-1, TREM-1 and IL-1beta. Most importantly, genes involved in innate immunity such as FCN1 and SEPP1 were found down-regulated. Many changes in cytokine expression demonstrated in our experiments were also found in HIV-1 infected individuals. These data indicate that the isu domain of gp41 has a broad impact on gene expression and cytokine release and therefore may be involved in HIV-1 induced immunopathogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cytokines / metabolism*
  • Enzyme-Linked Immunosorbent Assay
  • Gene Expression Regulation / immunology*
  • HIV Envelope Protein gp41 / immunology*
  • HIV Envelope Protein gp41 / metabolism*
  • HIV-1 / genetics*
  • HIV-1 / immunology
  • Humans
  • Leukocytes, Mononuclear / metabolism*
  • Microarray Analysis
  • Molecular Sequence Data
  • Peptides / genetics
  • Polymorphism, Single Nucleotide / genetics
  • Protein Structure, Tertiary / genetics
  • Real-Time Polymerase Chain Reaction


  • Cytokines
  • HIV Envelope Protein gp41
  • Peptides
  • gp41 protein, Human immunodeficiency virus 1

Grant support

The authors thank the German AIDS Foundation ( and the Berliner Sparkassenstiftung Medizin ( for financial support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.