A repetitive sequence of Epstein–Barr virus nuclear antigen 6 comprises overlapping T cell epitopes which induce HLA-DR-restricted CD4+ T lymphocytes

• Published in: International immunology Vol. 12; no. 3; pp. 281 - 293
• Main Authors: Rajnavölgyi, Éva, Nagy, Noémi, Thuresson, Britt, Dosztányi, Zsuzsa, Simon, Ágnes, Simon, István, Karr, Robert W., Ernberg, Ingemar, Klein, Eva, Falk, Kerstin I.
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.03.2000; Oxford Publishing Limited (England)
• Subjects: ACIF anti-complement immunofluorescence; Adult; Amino Acid Sequence; Animals; APC antigen-presenting cell; Biotinylation; BL Burkitt's lymphoma; Carrier State - immunology; CD4-Positive T-Lymphocytes - immunology; CD4-Positive T-Lymphocytes - metabolism; Cells, Cultured; Clinical Medicine; CTL cytotoxic T lymphocyte; DC dendritic cell; Dendritic Cells - immunology; DNA, Viral - genetics; EBNA EBV nuclear antigen; EBV Epstein–Barr virus; Epitopes - chemistry; Epitopes - genetics; Epitopes - immunology; Epstein-Barr virus; Epstein-Barr Virus Infections - immunology; Epstein-Barr Virus Nuclear Antigens - chemistry; Epstein-Barr Virus Nuclear Antigens - genetics; Epstein-Barr Virus Nuclear Antigens - immunology; HA hemagglutinin; Hematologi; Hematology; Herpesvirus 4, Human - genetics; Herpesvirus 4, Human - immunology; HLA-DR alpha-Chains; HLA-DR Antigens - immunology; HLA-DRB1 Chains; HLA-DR–peptide interaction; human CD4+ T lymphocyte; Humans; IM infectious mononucleosis; Immunoglobulin Class Switching; Immunoglobulin G - immunology; Immunologic Memory - immunology; Klinisk medicin; L Cells (Cell Line); LCL lymphoblastoid cell line; LMP latent membrane protein; Lymphocyte Activation; Lymphokines - metabolism; Medical and Health Sciences; Medicin och hälsovetenskap; Mice; Molecular Sequence Data; PBMC peripheral blood mononuclear cells; PE phycoerythrin; Peptide Fragments - chemistry; Peptide Fragments - immunology; Repetitive Sequences, Amino Acid; SI stimulation index; TNF tumor necrosis factor; Transfection; virus-specific immunity; XLP X-linked lymphoproliferative disease
• ISSN: 0953-8178; 1460-2377; 1460-2377
• DOI: 10.1093/intimm/12.3.281

Most human adults carry the Epstein–Barr virus (EBV) and develop immunological memory against the structural and the virus-encoded cellular proteins. The EBV nuclear antigen 6 (EBNA6) elicits cytotoxic T cell responses and it also maintains a persistent antibody response. The majority of sera from EBV-seropositive individuals reacts with a synthetic peptide, p63, comprising 21 amino acids of a repetitive region of EBNA6. CD4+ T lymphocytes, with specificity for p63, could be recalled from the T cell repertoire of EBV carriers that expressed certain HLA-DR allotypes which were identified as good binders of p63 by an in vitro flow cytometric assay. Analysis of the HLA-DR/p63 interaction by molecular mechanics calculations indicated the presence of multiple overlapping epitopes which were predicted to bind in a HLA-DRB1 allo- and subtype-specific manner. Specific activation of p63-selected long-term CD4+ T cell cultures resulted in a proliferative response, in the production of IL-2 and in the secretion of high levels of tumor necrosis factor as measured by bioassays. Proliferation and cytokine production of p63-specific T cells could be induced by p63-loaded HLA-DR-matched antigen-presenting cells and by B cells co-expressing relevant HLA-DR molecules and EBNA6. Our results show that peptides of an EBNA6 repeat region induce CD4+ T cells which can react with EBNA6-carrying cells in many individuals. We suggest that these Th cells may be important in conditioning dendritic cells for initiation potent virus-specific immune responses, provide help for EBV-specific B cells, drive IgG isotype switch and support the sustained effector function of memory cytotoxic T lymphocytes.