title: Mature B cells are required for acute splenic infection, but not for establishment of latency, by murine gammaherpesvirus 68.
abstract: Murine gammaherpesvirus 68 (gamma HV-68; also referred to as MHV-68) is a gammaherpesvirus which infects murid rodents. Previous studies showed that CD8 T cells are important for controlling gamma HV-68 replication during the first 2 weeks of infection and suggested a role for B cells in latent or persistent gamma HV-68 infection. To further define the importance of B cells and CD8 T cells during acute and chronic gamma HV-68 infection, we examined splenic infection in mice with null mutations in the transmembrane domain of the mu-heavy-chain constant region (MuMT; B-cell and antibody deficient) or in the beta2-microglobulin gene (beta2 -/-; CD8 deficient). Immunocompetent mice infected intraperitoneally with gamma HV-68 demonstrated peak splenic titers 9 to 10 days postinfection, cleared infectious virus 15 to 20 days postinfection, and harbored low levels of latent virus at 6 weeks postinfection. Beta2-/- mice showed peak splenic gamma HV-68 titers similar to those of normal mice but were unable to clear infectious virus completely from the spleen, demonstrating persistent infectious virus 6 weeks postinfection. These data indicate that CD8 T cells are important for clearing infectious gamma HV-68 from the spleen. Infected MuMT mice did not demonstrate detectable infectious gamma HV-68 in the spleen at any time after infection, indicating that mature B lymphocytes are necessary for acute splenic infection by gamma HV-68. Despite the lack of measurable acute infection, MuMT spleen cells harbored latent virus 6 weeks postinfection at a level about 100-fold higher than that in normal mice. These data demonstrate establishment of latency by a herpesvirus in an organ in the absence of acute viral replication in that organ. In addition, they demonstrate that gamma HV-68 can establish latency in a cell type other than mature B lymphocytes.
authors.affiliation: Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Weck
authors.forename: M L
authors.initials: ML
authors.lastname: Barkon
authors.forename: L I
authors.initials: LI
authors.lastname: Yoo
authors.forename: S H
authors.initials: SH
authors.lastname: Speck
authors.forename: I V
authors.initials: IV
authors.lastname: Virgin HW
mesh_terms: D000208:Acute Disease; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D002454:Cell Differentiation; D018142:Gammaherpesvirinae / Q000502:physiology*; D006566:Herpesviridae Infections / Q000276:immunology*; D051379:Mice; D013154:Spleen / Q000276:immunology / Q000473:pathology / Q000821:virology*; D014775:Virus Activation; D017735:Virus Latency