Characterizaton of gamma delta T cells in Marek's disease virus (Gallid herpesvirus 2) infection of chickens.

Immunity against Marek's disease (MD), caused by Gallid herpesvirus 2 (GaHV-2), in chickens is mediated by both innate and adaptive responses. The present study evaluated the effects of GaHV-2 infection on distribution and frequency of γδ T cells in tissues, as well as their expression of cytokines. We found that the infected chickens had significantly higher number of γδ T cells in their spleens by 10 and 21 days post-infection (d.p.i.) and nearly 100% of these γδ T cells were CD8+ at 21 d.p.i. Conversely, the number of γδ T cells in the cecal tonsils of GaHV-2-infected birds decreased compared to uninfected birds. Splenic γδ T cells had up-regulated expression of interferon-γ early in infection followed by simultaneous gene expression of interleukin-10 during the later phases. In conclusion, these results suggest a potential role for γδ T cells in host response to GaHV-2 and further elucidate the underlying immunological mechanisms of interactions between this virus and its host.