Submitted to: Virology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/12/2007
Publication Date: 4/4/2008
Citation: Abdul-Careem, M.F., Hunter, B.D., Sarson, A.J., Parvizi, P., Haghighi, H.R., Read, L., Heidari, M., Sharif, S. 2008. Host responses are induced in feathers of chickens infected with Marek's disease virus. Virology. 370:323-332. Interpretive Summary: Marek's disease (MD), a virus induced cancer like disease of chickens, is considered as a major disease problem in commercial poultry. Vaccination has dramatically reduced the incidence of the disease, but very little is known about the immune response involved in protection against the disease. The objective of this research was to characterize the immune response of the host against MD virus (MDV) infection in the feather. Our studies showed that in addition to an increase in number of MDV particles, a gradual increase in infiltration of subsets of an immune cell know as T cell into feather pulp of infected chickens was noted on day 4 and peaked by day 10 post-infection. In parallel to increase in subsets of T cells, there was an enhancement of the expression of certain immune proteins termed cytokines as well as other immune related genes.The observation that the immune response against MDV infection starts in the feathers is important in developing strategies for better control of MDV replication in feathers, and thus minimizing or preventing horizontal transmission of MDV.
Technical Abstract: Control measures are effective in curtailing Marek’s disease virus (MDV) infection and replication in the feather follicle epithelium (FFE). Therefore, vaccinated birds, which subsequently become infected with MDV, shed the virulent virus although they remain protected against disease. The present study investigated host responses generated against MDV infection in the feathers. We observed that in parallel with an increase in viral genome load and viral replication in the feather, there was a gradual but progressive increase infiltration of CD4+ and CD8+ T cells into the feather pulp of MDV-infected chickens, starting on day 4 and peaking by day 10 post-infection. Concomitant with infiltration of T cells, the expression of interleukin (IL)-18, IL-6, interferon (IFN)-gamma and major histocompatibility complex class I was significantly enhanced in the feather pulp of MDV-infected chickens. The finding that host responses are generated in the feather may be exploited for developing strategies to control MDV infection in the FFE, thus preventing horizontal virus transmission.