title: T cell responses to bluetongue virus are directed against multiple and identical CD4+ and CD8+ T cell epitopes from the VP7 core protein in mouse and sheep.
abstract: Bluetongue virus (BTV), an economically important orbivirus of the Reoviridae family, is a non-enveloped, dsRNA virus that causes a haemorrhagic disease mainly in sheep, but little is known of the cellular immunity elicited against BTV. We observed that vaccination of interferon type I-deficient mice (IFNAR((-/-))), or inoculation of the wild type C57BL/6 strain with BTV-8, induced a strong T cell response. Therefore, we proceeded to identify some of the T cell epitopes targeted by the immune system. We selected, using H-2(b)-binding predictive algorithms, 3 major histocompatibility complex (MHC)-class II-binding peptides and 7 MHC-class I binding peptides from the BTV-8 core protein VP7, as potential T cell epitopes. Peptide binding assays confirmed that all 7 MHC-class I predicted peptides bound MHC-class I molecules. Three MHC-class I and 2 MHC-class II binding peptide consistently elicited peptide-specific IFN-γ production (as measured by ELISPOT assays) in splenocytes from C57BL/6 BTV-8-inoculated mice and IFNAR((-/-))-vaccinated mice. The functionality of these T cells was confirmed by proliferation and cytotoxicity assays. Flow cytometry analysis demonstrated that CD8(+) T cells responded to MHC-class I binding peptides and CD4(+) T cells to MHC-class II binding peptides. Importantly, these 5 epitopes were also able to induced IFN-γ production in sheep inoculated with BTV-8. Taken together, these data demonstrate the activation of BTV-specific T cells during infection and vaccination. The characterisation of these novel T cell epitopes may also provide an opportunity to develop DIVA-compliant vaccination approach to BTV encompassing a broad-spectrum of serotypes.
authors.affiliation: Centro de Investigación en Sanidad Animal (CISA-INIA), Instituto Nacional de Investigación Agraria y Alimentaria, Valdeolmos, Madrid, Spain.
authors.forename: José-Manuel
authors.initials: JM
authors.lastname: Rojas
authors.forename: Teresa
authors.initials: T
authors.lastname: Rodríguez-Calvo
authors.forename: Lourdes
authors.initials: L
authors.lastname: Peña
authors.forename: Noemí
authors.initials: N
authors.lastname: Sevilla
mesh_terms: D000465:Algorithms; D000818:Animals; D001820:Bluetongue virus / Q000276:immunology* / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000276:immunology* / Q000378:metabolism; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000276:immunology / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism; D007111:Immunity, Cellular / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding / Q000276:immunology; D012756:Sheep / Q000276:immunology / Q000378:metabolism; D014758:Viral Core Proteins / Q000276:immunology* / Q000378:metabolism
chemical_list: D018984:Epitopes, T-Lymphocyte; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D010455:Peptides; D014758:Viral Core Proteins; C066862:VP7 protein, orbivirus; D007371:Interferon-gamma