title: Activation of Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) lytic replication by human cytomegalovirus.
abstract: The majority of Kaposi's sarcoma-associated herpesvirus (KSHV)-infected cells identified in vivo contain latent KSHV, with lytic replication in only a few percent of cells, as is the case for the cells of Kaposi's sarcoma (KS) lesions. Factors that influence KSHV latent or lytic replication are not well defined. Because persons with KS are often immunosuppressed and susceptible to many infectious agents, including human cytomegalovirus (HCMV), we have investigated the potential for HCMV to influence the replication of KSHV. Important to this work was the construction of a recombinant KSHV, rKSHV.152, expressing the green fluorescent protein (GFP) and neo (conferring resistance to G418). The expression of GFP was a marker of KSHV infection in cells of both epithelial and endothelial origin. The rKSHV.152 virus was used to establish cells, including human fibroblasts (HF), containing only latent KSHV, as demonstrated by latency-associated nuclear antigen expression and Gardella gel analysis. HCMV infection of KSHV latently infected HF activated KSHV lytic replication with the production of infectious KSHV. Dual-color immunofluorescence detected both the KSHV lytic open reading frame 59 protein and the HCMV glycoprotein B in coinfected cells, and UV-inactivated HCMV did not activate the production of infectious KSHV-GFP. In addition, HCMV coinfection increased the production of KSHV from endothelial cells and activated lytic cycle gene expression in keratinocytes. These data demonstrate that HCMV can activate KSHV lytic replication and suggest that HCMV could influence KSHV pathogenesis.
authors.affiliation: Department of Laboratory Medicine, University of Washington, and Program in Infectious Diseases, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA. vieiraj@u.washington.edu
authors.forename: J
authors.initials: J
authors.lastname: Vieira
authors.forename: P
authors.initials: P
authors.lastname: O'Hearn
authors.forename: L
authors.initials: L
authors.lastname: Kimball
authors.forename: B
authors.initials: B
authors.lastname: Chandran
authors.forename: L
authors.initials: L
authors.lastname: Corey
mesh_terms: D003587:Cytomegalovirus / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000821:virology; D015967:Gene Expression Regulation, Viral; D019288:Herpesvirus 8, Human / Q000502:physiology*; D006801:Humans; D011995:Recombination, Genetic; D014407:Tumor Cells, Cultured; D014775:Virus Activation; D014779:Virus Replication