CD8+ T cell responses to lytic EBV infection: late antigen specificities as subdominant components of the total response

J Immunol. 2013 Dec 1;191(11):5398-409. doi: 10.4049/jimmunol.1301629. Epub 2013 Oct 21.

Abstract

EBV elicits primary CD8(+) T cell responses that, by T cell cloning from infectious mononucleosis (IM) patients, appear skewed toward immediate early (IE) and some early (E) lytic cycle proteins, with late (L) proteins rarely targeted. However, L Ag-specific responses have been detected regularly in polyclonal T cell cultures from long-term virus carriers. To resolve this apparent difference between responses to primary and persistent infection, 13 long-term carriers were screened in ex vivo IFN-γ ELISPOT assays using peptides spanning the two IE, six representative E, and seven representative L proteins. This revealed memory CD8 responses to 44 new lytic cycle epitopes that straddle all three protein classes but, in terms of both frequency and size, maintain the IE > E > L hierarchy of immunodominance. Having identified the HLA restriction of 10 (including 7 L) new epitopes using memory CD8(+) T cell clones, we looked in HLA-matched IM patients and found such reactivities but typically at low levels, explaining why they had gone undetected in the original IM clonal screens. Wherever tested, all CD8(+) T cell clones against these novel lytic cycle epitopes recognized lytically infected cells naturally expressing their target Ag. Surprisingly, however, clones against the most frequently recognized L Ag, the BNRF1 tegument protein, also recognized latently infected, growth-transformed cells. We infer that BNRF1 is also a latent Ag that could be targeted in T cell therapy of EBV-driven B-lymphoproliferative disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / virology
  • Cells, Cultured
  • Enzyme-Linked Immunospot Assay
  • HLA Antigens / metabolism
  • Herpesvirus 4, Human / immunology*
  • Humans
  • Immunodominant Epitopes / immunology
  • Immunodominant Epitopes / metabolism
  • Infectious Mononucleosis / immunology*
  • Interferon-gamma / metabolism
  • Molecular Sequence Data
  • Peptide Fragments / immunology
  • Peptide Fragments / metabolism
  • Protein Binding
  • Viral Envelope Proteins / immunology
  • Viral Envelope Proteins / metabolism
  • Virus Latency / immunology

Substances

  • HLA Antigens
  • Immunodominant Epitopes
  • P140 protein, Epstein-barr virus
  • Peptide Fragments
  • Viral Envelope Proteins
  • Interferon-gamma