Establishment of a cell-based assay for screening of compounds inhibiting very early events in cytomegalovirus replication cycle and characterization of a compound identified using the assay

Department of Virology I, National Institute of Infectious Diseases, Tokyo; Department of Biosciences, Teikyo University of Science and Technology, Yamanashi; Department of Pediatrics, Asahikawa Medical College, Hokkaido; Department of Pathology II, Hamamatsu Medical University, Shizuoka, Japan

^* To whom correspondence should be addressed. Email: ninoue{at}nih.go.jp.

	Abstract

To simplify the detection of infectious human cytomegalovirus (HCMV), we generated a cell line that produced luciferase in a dose-dependent manner upon HCMV infection. Using this cell line, anti-HCMV compounds were identified from a diverse library of 9600 compounds. One of them, 1-(3,5-dichloro-4-pyridyl)piperidine-4-carboxamide (DPPC), was effective against HCMV (Towne strain) infection of human lung fibroblast cells at a 50% effective concentration of 2.5 µM. DPPC also inhibited the growth of clinical HCMV isolates, and guinea pig and mouse CMVs. Experiments using various timeframes for treatment of the cells with DPPC demonstrated that DPPC was effective during the first 24 hrs after HCMV infection. DPPC treatment decreased not only viral DNA replication but also IE1 and IE2 expression at mRNA and protein levels in the HCMV-infected cells. However, DPPC did not inhibit the attachment of HCMV particles to the cell surface. DPPC is a unique compound that targets the very early phase of CMV infection, probably by disrupting a pathway that is important after viral entry but before immediate-early gene expression.