Modulatory effects of human herpes virus-7 on cytokine synthesis and cell proliferation in human peripheral blood mononuclear cell cultures

Human herpes virus-7 (HHV-7) infects cells of the immune system and thus ma y modulate their function, To investigate the potential immunomodulatory ef fects of this virus, rue performed an in vitro study in which we investigat ed effects of HHV-7 on the synthesis of several hey immunomodulatory cytoki nes, i.e. tumor necrosis factor alpha (TNF-alpha), interleukin-2 (IL-2), in terferon-gamma (IFN-gamma), IL-4, IL-6, and transforming growth factor beta (TGF-beta), This was examined after in vitro infection of human peripheral blood mononuclear cells (PBMC) with HHV-7. We found elevated levels of TNF -alpha, TGF-beta, and IFN-gamma in the supernatants of HHV-7-infected cells . By reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, usi ng cytokine-specific primers, we found that levels of TNF-alpha, TGF-beta, and IFN-gamma mRNA were increased in the infected cells. The HHV-7 infectio n also significantly (P < 0.05) decreased the production of IL-2 front acti vated, IL-2-producing PBMC. Furthermore, mitogen- and cytokine-induced cell ular proliferative responses of human PBMC were found to be significantly ( P < 0.05) downregulated by this virus. On the other hand, HHV-7 did not aff ect IL-4 and IL-6 synthesis. Overall, our results indicate that HHV-7 infec tion causes significant immunomodulatory effects with regard to cytokine sy nthesis in these cells as well as inhibiting lymphocyte proliferation by va rious stimuli.