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Updated: Oct 5, 2026
An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection
Published on: December 10, 2013
Role of interleukin-18 in peripheral blood mononuclear cells infected with human herpes virus type 6
A Arena1, D Iannello, D Gazzara
1Institute of Medical Microbiology, Policlinico Universitario, University of Messina, Via C. Valeria, I-98125 Messina, Italy.
Objective:
Interleukin 18 (IL-18) production represents a critical step in the polarization of the Th1 immune response. Human herpes virus type 6 (HHV-6) possesses a peculiar tropism for immunocompetent cells. To understand the relationships among immunocompetent cells, HHV-6 and cytokines, the role of IL-18 during infection of peripheral blood mononuclear cells (PBMC) with HHV-6 was evaluated.
Methods:
PBMC were obtained from healthy HHV-6-seronegative donors, after centrifugation of heparinized venous blood over a Ficoll-Hypaque gradient. Supernatants from PBMC were analyzed for the presence of cytokines. To study the effects of exogenous recombinant human (rh) IL-18 on HHV-6 replication, the number of cells expressing viral antigens and the amount of extracellular virus were analysed.
Results:
No basal production of IL-18 was found in supernatants of unstimulated PBMC. Appreciable amounts of the cytokine were produced by lipopolysaccharide (LPS)-stimulated PBMC. HHV-6 infection of LPS-treated PBMC downregulated IL-18 production. It was found that the addition of rhIL-18 to HHV-6-infected PBMC downregulated the percentage of antigen-positive cells and the release of extracellular virus.
Conclusion:
Impairment of IL-18 release, which is involved in the induction of antiviral cytokines, such as interferon-gamma, could represent a strategy of the virus to evade the immune response of the host.
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