Specific and nonspecific immune responses to Marek's disease virus

Marek's disease (MD) virus (MDV) has provided an important model to study i mmune responses against a lymphoma-inducing herpesvirus in its natural host . Infection in chickens starts with a lytic infection in B cells, followed by a latent infection in T cells and; in susceptible birds, T cell lymphoma s develop. Non-specific and specific immune responses are important for the control of virus infection and subsequent tumor development. Interferon-ga mma and nitric oxide are important for the control of virus replication dur ing the lytic phase of infection and are also important to prevent reactiva tion of MDV replication in latently infected and transformed cells. Cytotox ic T cells (CTLs) are the most important of the specific immune responses i n MDV. In addition to antigen-specific CTL against MDV proteins pp38, glyco protein B (gB), Meg, and ICP4, ICP27-specific CTL can also be detected as e arly as 6 to 7 days post infection. The epitope for gB recognized by CTLs f rom P2a (MHC: (BB19)-B-19) chickens has been localized to the Ero47III-BamH I (nucleotides 1515-1800) fragment. A proposed model for the interactions o f cytokines and immune responses as part of the pathogenesis of MD is discu ssed. (C) 2000 Elsevier Science Ltd. All rights reserved.