[Persistent/latent infection of human beta-herpesvirus]

Human cytomegalovirus(CMV) is a significant pathogen in immunocompromised individuals and neonates. Human herpesvirus 6(HHV-6) is a causative agent of exanthem subitum. These two viruses belong to beta-herpesvirus subfamily. Latency, a hallmark of all herpesvirus, remains poorly understood for beta-herpesvirus. We investigate maintenance and expression of the vira genome in an experimental latent infection using granulocyte-macrophage progenitors(GM-Ps) for CMV and monocytes/macrophages for HHV-6. To better understand beta-herpesvirus latency, we investigate the extent of viral gene expression in our latency system and found two novel classes of CMV latency associated transcripts(CLTs). Latent infection by CMV is accompanied by the presence of latency-associated transcripts and expression of immunogenic proteins. It is suggested that bone marrow-derived myeloid progenitors are an important natural site of CMV latency and peripheral blood derived monocytes/macrophages is important to maintain HHV-6 latency.