MYXOMA T2 PROTEIN AS A MODEL FOR POXVIRUS TNF RECEPTOR HOMOLOGS

Many poxviruses encode a plethora of immunomodulatory proteins, includ ing homologs of cellular cytokine receptors. These receptor mimics, al so referred to as viroceptors, are believed to function by binding and sequestering host cytokines thus preventing their signaling cascade p rior to receptor engagement. The M-T2 protein of myxoma virus is a TNF receptor homolog that has two distinct activities: the secreted dimer ic M-T2 protein binds and inhibits TNF alpha while the intracellular v ersion permits myxoma virus replication in infected T-lymphocytes by b locking the cellular apoptosis response to the virus infection. Studie s with M-T2 mutants reveal that distinct protein domains mediate these two anti-immune properties of this protein.