Herpesvirus disease pathogenesis is closely linked to host immune status. Murine gammaherpesvirus 68 (?HV68) provides a model for studying the outcome of chronic gammaherpesvirus infection in the immunocompetent versus immunodeficient host. ?HV68 infection of a wild-type mouse results in a limited, acute infection at the site of inoculation, followed by latent, disseminated infection in a variety of tissues and cell types. Although wild-type mice rarely display any virus-related pathology, interferon-gamma receptor- deficient hosts (IFN?R-/-) develop potentially lethal, systemic inflammatory disease. This immune-mediated pathology consists of multi-organ fibrotic tissue damage and vasculitis, associated with chronic reactivation of latent virus and persistent replication. Interestingly, many features of this disease are absent during chronic infection with a ?HV68 mutant lacking the antigen encoded by the M1 open reading frame (ORF) - even though this mutant virus is not impaired for either acute replication or establishment of a latent infection. The M1 antigen, which bears sequence homology to some pox virus serpins (although it lacks critical catalytic residues) and to the ?HV68 secreted high affinity chemokine binding protein M3, has been shown to regulate ?HV68 reactivation from latency. The mechanism by which M1 exerts this effect, and the extent of immune system involvement, is unknown. Throughout the course of latency, the ?HV68 antiviral response is not appreciably stimulated with one notable exception - the significant expansion of V24+ CD8+ T cells. We have recently shown that expression of the M1 antigen is required for this response. This application aims to study the potentially novel mechanism(s) by which the ?HV68 M1 gene product induces V24+ T cell activity, perhaps to self-limit reactivation from latency through expression of IFN-?, and the role such T cells might play in mediating chronic disease in an immunocompromised host. The following 3 aims are proposed:
Aim 1 : Characterize M1 transcript structure(s) and regulation of M1 gene expression.
Aim 2 : Define the mechanism of M1-induced V24+ T cell activation and its influence on T cell function.
Aim 3 : Define the role of M1 and V24+ T cells in regulating ?HV68 reactivation, latency, and virus-induced systemic inflammatory disease.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-IDM-M (03))
Program Officer
Beisel, Christopher E
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Emory University
Schools of Medicine
United States
Zip Code
O'Flaherty, Brigid M; Matar, Caline G; Wakeman, Brian S et al. (2015) CD8+ T Cell Response to Gammaherpesvirus Infection Mediates Inflammation and Fibrosis in Interferon Gamma Receptor-Deficient Mice. PLoS One 10:e0135719
O'Flaherty, Brigid M; Soni, Tanushree; Wakeman, Brian S et al. (2014) The murine gammaherpesvirus immediate-early Rta synergizes with IRF4, targeting expression of the viral M1 superantigen to plasma cells. PLoS Pathog 10:e1004302
Wakeman, Brian S; Johnson, L Steven; Paden, Clinton R et al. (2014) Identification of alternative transcripts encoding the essential murine gammaherpesvirus lytic transactivator RTA. J Virol 88:5474-90
Collins, Christopher M; Speck, Samuel H (2012) Tracking murine gammaherpesvirus 68 infection of germinal center B cells in vivo. PLoS One 7:e33230
Gray, Kathleen S; Forrest, J Craig; Speck, Samuel H (2010) The de novo methyltransferases DNMT3a and DNMT3b target the murine gammaherpesvirus immediate-early gene 50 promoter during establishment of latency. J Virol 84:4946-59
Paden, Clinton R; Forrest, J Craig; Moorman, Nathaniel J et al. (2010) Murine gammaherpesvirus 68 LANA is essential for virus reactivation from splenocytes but not long-term carriage of viral genome. J Virol 84:7214-24
Collins, Christopher M; Boss, Jeremy M; Speck, Samuel H (2009) Identification of infected B-cell populations by using a recombinant murine gammaherpesvirus 68 expressing a fluorescent protein. J Virol 83:6484-93