Infection of Dendritic Cells by a gamma 2-Herpesvirus Induces Functional Modulation

• Published in: The Journal of immunology (1950) 2005-09, Vol.175 (5), p.3225-3234
• Main Authors: Flano, Emilio, Kayhan, Basak, Woodland, David L, Blackman, Marcia A
• Format: Article
• Language: English
• ISSN: 0022-1767
• DOI: 10.4049/jimmunol.175.5.3225

The murine gamma -herpesvirus-68 ( gamma HV68) establishes viral latency in dendritic cells (DCs). In the present study, we examined the specific consequences of DC infection by gamma HV68, both in vivo and in vitro. Ex vivo analysis of infected mice showed that the virus colonizes respiratory DCs very early after infection and that all subsets of splenic DCs analyzed are viral targets. We have developed and characterized an in vitro model of gamma HV68 infection of DCs. Using this model, we demonstrated that viral infection neither induces full DC maturation nor interferes with exogenous activation, which is assessed by cell surface phenotypic changes. However, whereas gamma HV68 infection alone failed to elicit cytokine secretion, IL-10 secretion of exogenously activated DCs was enhanced. Furthermore, gamma HV68-infected DCs efficiently stimulated virus-specific T cell hybridomas but failed to induce alloreactive stimulation of normal T cells. These data indicate that viral infection doesn't interfere with Ag processing and presentation but does interfere with the ability of DCs to activate T cells. The inhibition of T cell activation was partially reversed by blocking IL-10. Analysis of infected mice shows elevated levels of IL-10 expression in DCs and that lack of endogenous IL-10 is associated with decreased gamma HV68 long-term latency. Taken together, these observations indicate that gamma 2-herpesvirus infection of DCs is a mechanism of viral immune evasion, partially mediated by IL-10.