Phenotypic characterization of gamma delta (γδ) T cells in chickens infected with or vaccinated against Marek's disease virus

Marek's disease (MD) vaccines reduce the incidence of MD but cannot control virus shedding. To develop new vaccines, it is essential to elucidate mechanisms of immunity to Marek's disease virus (MDV) infection. In this regard, gamma delta (gamma delta) T cells may play a significant role in prevention of viral spread and tumor surveillance. Here we demonstrated that MDV vaccination induced interferon (IFN)-gamma(+)CD8 alpha(+) gamma delta T cells and transforming growth factor (TGF)-beta(+) gamma delta T cells in lungs. gamma delta T cells from MDV-infected chickens exhibited cytotoxic activity. Importantly, gamma delta T cells from the vaccinated/challenged group exhibited maximum cytotoxic activity following ex vivo stimulation. These results suggest that MDV vaccines activate effector gamma delta T cells which may be involved in the development of protective immune responses against MD. Further, it was demonstrated that MDV infection increases the frequency of a subpopulation of gamma delta T cells expressing membrane-bound TGF-beta in MDV-infected birds.

Automated summary

This study demonstrates that vaccination against Marek's disease virus (MDV) activates effector γδT cells, which may play a crucial role in protective immune responses against MDV.