Increased level of IL-32 during human immunodeficiency virus infection suppresses HIV replication

Immunol Lett. 2008 May 15;117(2):161-7. doi: 10.1016/j.imlet.2008.01.007. Epub 2008 Feb 11.

Abstract

Interleukin-32 was recently identified as a pro-inflammatory cytokine produced by T-lymphocytes, natural killer cells, epithelial cells, and blood monocytes. IL-32 is induced by IFN-gamma in a time-dependent manner suggesting a role for IL-32 in innate and adaptive immune responses. In this study we present evidence that Human immunodeficiency virus promotes interleukin-32 production at both mRNA and protein levels. Our results showed that there is a 74% increase in the serum levels of IL-32 among HIV patients as compared to healthy individuals. There was a three-fold increase in the promoter activity of the IL-32 in the present infections HIV clone. This increase in IL-32 promoter activity was substantiated by increased IL-32 mRNA and protein levels. We have also demonstrated that IL-32 suppresses HIV replication. Our results show that HIV LTR activity was increased by more than six-folds when endogenous IL-32 was knocked down by IL-32-specific siRNA whereas it decreased by one-fold when IL-32 was over expressed in the cells. Similarly a more than two-fold increase and a 50% decrease in HIV p24 values were noted when IL-32 was knocked down and when IL-32 was over expressed in the cells, respectively. Our present work shows that raised IL-32 levels in HIV infection may in turn hamper HIV replication; one of the protective mechanisms of nature.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cloning, Molecular
  • Feedback, Physiological
  • Gene Expression Regulation
  • HIV / physiology*
  • HIV Core Protein p24 / genetics
  • HIV Core Protein p24 / immunology
  • HIV Core Protein p24 / metabolism
  • HIV Infections / blood
  • HIV Infections / genetics
  • HIV Infections / immunology*
  • HIV Long Terminal Repeat / genetics
  • HIV Long Terminal Repeat / immunology
  • Humans
  • Interleukins / blood
  • Interleukins / genetics*
  • Interleukins / immunology*
  • RNA, Messenger / analysis
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / immunology
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Transfection
  • Virus Replication / immunology*

Substances

  • HIV Core Protein p24
  • IL32 protein, human
  • Interleukins
  • RNA, Messenger
  • RNA, Small Interfering
  • Recombinant Proteins