Epstein-Barr virus (EBV) infection in infectious mononucleosis: virus latency, replication and phenotype of EBV-infected cells

J Pathol. 1997 Jun;182(2):151-9. doi: 10.1002/(SICI)1096-9896(199706)182:2<151::AID-PATH824>3.0.CO;2-3.


Primary Epstein-Barr virus (EBV) infection may manifest itself as a benign lymphoproliferative disorder, infections mononucleosis (IM). EBV infection has been characterized in lymphoreticular tissues from nine patients with IM using the abundantly expressed EBV-encoded nuclear RNAs (EBERs) as a marker of latent infection. Expression of the virus-encoded nuclear antigen (EBNA) 2 and of the latent membrane protein (LMP) 1 was seen in variable proportions of cells in all cases. Double labelling revealed heterogeneous expression patterns of these proteins. Thus, in addition to cells revealing phenotypes consistent with latencies I (EBNA2-/LMP1-) and III (EBNA2+/LMP1+), cells displaying a latency II pattern (EBNA2-/LMP1+) were observed. Cells expressing EBNA2 but not LMP1 were also detected; whilst this may represent a transitory phenomenon, the exact significance of this observation is at present uncertain. EBER-specific in situ hybridization in conjunction with immunohistochemistry revealed expression of the EBERs mainly in B-lymphocytes, many of which showed features of plasma cell differentiation. By contrast, convincing evidence of latent EBV infection was not found in T-cells, epithelial or endothelial cells. Double-labelling immunohistochemistry revealed expression of the replication-associated BZLF1 protein in small lymphoid cells, often showing plasmacytoid differentiation. There was no unambiguous expression of this protein in other cell types. These results suggest that B-cells are the primary target of EBV infection and that plasma cells may be a source of infectious virus found in the saliva of IM patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Viral / analysis
  • B-Lymphocytes / virology
  • Epstein-Barr Virus Nuclear Antigens
  • Herpesvirus 4, Human / physiology*
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization
  • Infectious Mononucleosis / virology*
  • Phenotype
  • Plasma Cells / virology
  • Viral Matrix Proteins / analysis
  • Virus Latency*
  • Virus Replication*


  • Antigens, Viral
  • EBV-associated membrane antigen, Epstein-Barr virus
  • Epstein-Barr Virus Nuclear Antigens
  • Viral Matrix Proteins