As such, an important consideration for interpretation of our findings is that much of the virus-specific T cell response could be directed against peptides derived from genes expressed only during the immediate early or early phase of replication. Indeed, continuous surveillance by CD8 + T cells recognizing immediate-early antigenic epitopes during latent murine CMV infection blocks the transcriptional activity of viral genes downstream of that gene. The gene discussed is CD8A; the disease is cytomegalovirus infection.