DESCRIPTION (provided by applicant): Monkey Herpes B virus (BV) has been reported to cause lethal infections in humans. BV is indigenous to macaque monkeys used in research, and is a potential group B bioterrorism agent. Human disease is characterized by vesicular eruptions on the skin or mucous membranes that are indistinguishable from herpetic lesions caused by HSV-1 or HSV-2. Unlike typical HSV infections that rarely lead to central nervous system involvement, BV causes a rapidly ascending myelitis and encephalitis that almost always leads to death. Because of the threat to handlers and potential for use in bioterrorism, diagnosis and treatment of BV infection need to be improved. We propose to develop new antiviral targets for HB involving cloning of selected DNA replication-related genes, expression and isolation of the protein products, and characterization of the substrate and inhibitor properties of the enzymes. Our expertise and extensive libraries of compounds that inhibit the HSV enzymes will be the starting point in drug discovery. Because of the nature of the pathology of BV infection in humans, we will focus initial efforts in this phase I program on thymidine kinase (TK), because inhibitors of the HSV types 1 and 2 TKs protect mice from lethal encephalitis. The specific aims are: 1) to clone and overexpress the BV TK gene in eukaryotic expression vectors, and purify sufficient quantities of the enzyme for study; 2) to fully characterize the enzymatic properties of BV TK; 3) to screen a library of N2-phenylguanine derivatives that have a wide range of affinities for the HSV TKs; 4) to synthesize new analogs to improve potency and selectivity; and 5) to test promising compounds and antiherpes drugs in vitro for anti-BV activity in cell cultures.