The immunogenicity of human and murine cytomegaloviruses

Cytomegaloviruses are strictly host-species-specific. During an aeon of co-evolution, virus and host have found an arrangement: the productive and cytopathogenic cycle of viral gene expression is held in check by the host's immune response. As a consequence, cytomegalovirus disease is restricted to the immunocompromised host. The virus has evolved strategies to avoid its elimination and eventually hides itself in a silent state, referred to as 'viral latency'. Redundant molecular mechanisms have been identified by which cytomegaloviruses interfere with antigen presentation pathways to 'evade' immune control. In the annual period covered by this review, the IE1 protein was revisited as an immunodominant antigen of human cytomegalovirus and the identification of a first antigenic early-phase peptide of murine cytomegalovirus that escapes viral immunosubversive mechanisms may initiate a period of research on the immune control of cytomegaloviruses 'beyond immune evasion'.