Protection from RNA and DNA viruses by IL-32

Jarod Zepp, Claudia Nold, Charles Dinarello, Marcel Nold

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35 Citations (Scopus)


Several studies have documented a proinflammatory role for IL-32, which induces IL-1alpha, IL-1beta, IL-6, TNF, and chemokines via NF-kappaB, p38MAPK, and AP-1. However, IL-32 also participates in the responses to infection with viruses such as HIV-1 and influenza. In this study, we explored these antiviral properties of IL-32. Vital staining assays demonstrated that low concentrations (5-10 ng/ml) of rIL-32gamma protected epithelial WISH cells from vesicular stomatitis virus-induced cell death. By lactate dehydrogenase assays, treatment with IL-32gamma resulted in a 3- to 4-fold decrease in viral load. Specific silencing of IL-32 revealed that the antiviral responses triggered by the synthetic analogs of ssRNA viruses (polyuridine) and dsRNA viruses (polyinosinic-polycytidylic acid) were significantly weaker (2- to 3-fold more virus) in WISH cells in the absence of IL-32. Importantly, we discovered that the polyinosinic-polycytidylic acid-induced increase in production of IFN-alpha in human PBMC was nearly completely abolished when IL-32 was silenced. Moreover, we observed that IL-32 antagonizes the DNA virus HSV-2 in epithelial Vero cells as well as in human umbilical cord endothelial cells, as production of HSV-2 increased 8-fold upon silencing of IL-32 (p <0.001). Mechanistically, we found that IL-32 used the PKR-eIF-2alpha as well as the MxA antiviral pathways. Unexpectedly, a considerable part of the antiviral properties of IL-32 was not dependent on IFNs; specific blockade of IFN activity reduced the antiviral properties of IL-32 only moderately. In conclusion, these data suggest a central role for IL-32 in the immune response to RNA and DNA viruses, which may be exploitable for clinical use in the future.
Original languageEnglish
Pages (from-to)4110 - 4118
Number of pages9
JournalJournal of Immunology
Issue number7
Publication statusPublished - 2011

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