title: HLA-A*0201-restricted CD8+ T-cell epitopes identified in dengue viruses.
abstract: BACKGROUND
  All four dengue virus (DV) serotypes (D1V, D2V, D3V and D4V) can cause a series of disorders, ranging from mild dengue fever (DF) to severe dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS). Previous studies have revealed that DV serotype-specific CD8(+) T cells are involved in controlling DV infection. Serotype cross-reactive CD8(+) T-cells may contribute to the immunopathogenesis of DHF/DSS. The aim of the study was to identify HLA-A*0201-binding peptides from four DV serotypes. We then examined their immunogenicity in vivo and cross-reactivity within heterologous peptides.
  
  
  METHODS
  D1V-derived candidate CD8(+) T-cell epitopes were synthesized and evaluated for their affinity to the HLA-A*0201 molecule. Variant peptides representing heterologous D2V, D3V, D4V serotypes were synthesized. The immunogenicity of the high-affinity peptides were evaluated in HLA-A*0201 transgenic mice.
  
  
  RESULTS
  Of the seven D1V-derived candidate epitopes [D1V-NS4a(56-64)(MLLALIAVL), D1V-C(46-54)(LVMAFMAFL), D1V-NS4b(562-570)(LLATSIFKL), D1V-NS2a(169-177)(AMVLSIVSL), D1V-NS4a(140-148)(GLLFMILTV), D1V-NS2a(144-152)(QLWAALLSL) and D1V-NS4b(183-191)(LLMRTTWAL)], three peptides [D1V-NS4a(140-148), D1V-NS2a(144-152) and D1V-NS4b(183-191)] had a high affinity for HLA-A*0201 molecules. Moreover, their variant peptides for D2V, D3V and D4V [D2V-NS4a(140-148)(AILTVVAAT), D3V-NS4a(140-148)(GILTLAAIV), D4V-NS4a(140-148)(TILTIIGLI), D2V-NS2a(144-152)(QLAVTIMAI), D3V-NS2a(144-152)(QLWTALVSL), D4V-NS2a(143-151)(QVGTLALSL), D2V-NS4b(182-190)(LMMRTTWAL), D3V-NS4b(182-190) (LLMRTSWAL) and D4V-NS4b(179-187)(LLMRTTWAF)] also had a high affinity for HLA-A*0201 molecules. Furthermore, CD8+ T cells directed to these twelve peptides were induced in HLA-A*0201 transgenic mice following immunization with these peptides. Additionally, cross-reactivity within four peptides (D1V-NS4b(183-191), D2V-NS4b(182-190), D3V-NS4b(182-190) and D4V-NS4b(179-187)) was observed.
  
  
  CONCLUSIONS
  Two novel serotype-specific HLA-A*0201-restricted CD8(+) T-cell epitopes (NS4a(140-148) and NS2a(144-152)) and one cross-reactive HLA-A*0201-restricted CD8(+) T-cell epitopes which is similar to a previously identified epitope were identified in D1V-D4V. Combining prediction algorithms and HLA transgenic mice is an effective strategy to identify HLA-restricted epitopes. Serotype-specific epitopes would be used to determine the protective role of serotype-specific CD8(+) T cells, while cross-reactive epitopes may provide assistance in exploring the role of serotype cross-reactive CD8(+) T cells in the immunopathogenesis of DHF/DSS.
authors.affiliation: Department of Microbiology and Immunology, Wenzhou Medical College, Wenzhou, China.
authors.forename: Zhi-Liang
authors.initials: ZL
authors.lastname: Duan
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.forename: Zhi-Bin
authors.initials: ZB
authors.lastname: Wang
authors.forename: Ke-Dong
authors.initials: KD
authors.lastname: Xia
authors.forename: Jiang-Long
authors.initials: JL
authors.lastname: Guo
authors.forename: Wen-Quan
authors.initials: WQ
authors.lastname: Liu
authors.forename: Jin-Sheng
authors.initials: JS
authors.lastname: Wen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002460:Cell Line; D003429:Cross Reactions / Q000276:immunology; D003716:Dengue Virus / Q000145:classification / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000276:immunology*; D005260:Female; D015789:HLA-A2 Antigen / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000276:immunology
chemical_list: D018984:Epitopes, T-Lymphocyte; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D017361:Viral Nonstructural Proteins