Murine γ-herpesvirus-68: a mouse model for infectious mononucleosis?

Abstract

Herpesviruses are double-stranded DNA viruses that establish life-long latency in the host and are important human pathogens1. They can be classified into three major groups, largely determined by the growth characteristics of the virus and the tissue types in which viral latency is established. The a-herpesviruses include herpes simplex virus, the b-herpesviruses include cytomegalovirus and the lymphotropic g-herpesviruses include Epstein–Barr virus (EBV) and Kaposi's sarcoma associated herpesvirus (KSHV or human herpesvirus-8). EBV is ubiquitous in the human population. The virus establishes a lytic infection in the oropharynx and life-long latency, predominantly in B cells. The latent stage is benign in individuals with a competent immune system but is associated with the development of a range of malignancies in immunocompromised individuals. Infectious mononucleosis is a common sequela of primary EBV infection. The syndrome is characterized by lymphadenopathy, splenomegaly, heterophilic antibodies and peripheral blood lymphocytosis with atypical lymphocytes, and usually resolves spontaneously. Interestingly, infectious mononucleosis occurs frequently in developed countries where initial EBV infection is delayed until adolescence or adulthood, but is not observed in developing countries where EBV infection occurs early in life. In many cases, infectious mononucleosis is the first clinical indication of EBV infection and the precise relationship of the syndrome with the lytic infection has not been determined.