title: Functional analysis of the CD4(+) T-cell response to Epstein-Barr virus: T-cell-mediated activation of resting B cells and induction of viral BZLF1 expression.
abstract: In contrast to the major role played by Epstein-Barr virus (EBV)-specific CD8(+) cytotoxic T-cell responses in immunosurveillance, recent studies have offered the apparently paradoxical suggestion that development of EBV-driven human B-cell lymphoproliferative disorders and tumors in SCID/hu mice is dependent on the presence of T cells, in particular CD4(+) T cells. This study presents a functional analysis of the CD4(+) T-cell response to EBV and shows that while CD4(+) T cells may be cytotoxic, they also express Th2 cytokines and CD40 ligand (gp39) and possess B-cell helper function. We show that EBV-specific CD4(+) T cells can provide non-HLA-restricted help for activation of resting B cells via a gp39-CD40-dependent pathway and are able to induce expression of BZLF1, a viral lytic cycle transactivator in latently infected resting B cells, ultimately resulting in rapid outgrowth of transformed B-cell colonies. These results support the proposal that CD4(+) T cells may play a key role in reactivation of latent EBV infection and may thus contribute to the pathogenesis of EBV-driven lymphoproliferative disorders.
authors.affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Fu
authors.forename: M J
authors.initials: MJ
authors.lastname: Cannon
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D020126:Brefeldin A / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D019013:CD40 Antigens / Q000378:metabolism; D023201:CD40 Ligand; D016207:Cytokines / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004854:Herpesvirus 4, Human / Q000276:immunology* / Q000502:physiology; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology / Q000378:metabolism; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*; D014775:Virus Activation; D017735:Virus Latency
chemical_list: D000998:Antiviral Agents; C063676:BZLF1 protein, Herpesvirus 4, Human; D019013:CD40 Antigens; D016207:Cytokines; D004268:DNA-Binding Proteins; D008562:Membrane Glycoproteins; D015534:Trans-Activators; D014764:Viral Proteins; D023201:CD40 Ligand; D020126:Brefeldin A