title: Nucleoprotein of influenza A virus is a major target of immunodominant CD8+ T-cell responses.
abstract: Influenza A virus causes annual epidemics and sporadic pandemics, resulting in significant morbidity and mortality worldwide. Vaccines are currently available; however, they induce a non-strain-cross protective humoral immune response directed against the rapidly mutating surface glycoproteins, and thus need to be updated annually. As T cells are directed against more conserved internal influenza proteins, a T-cell-based vaccine has the potential to induce long-lasting and cross-strain protective CD8(+) T-cell immunity, and in that way minimize the severity of influenza infection. However, to rationally design such vaccines, we need to identify immunogenic T-cell regions within the most antigenic viral proteins. In this study, we have used a systematic approach to identify immunodominant peptides in HLA-A2-negative donors. A broad range of CD8(+) T-cell responses were observed and 6/7 donors had an immunodominant response against the relatively conserved internal nucleoprotein (NP). Dissecting the minimal epitope regions within the immunogenic NP led to the identification of six novel immunodominant epitopes, which include a 12-mer and an 8-mer peptides. The majority of immunodominant epitopes was clustered within the carboxyl terminal 2/3 of the NP protein and were highly conserved. We also subjected NP to three common computer algorithms for epitope prediction and found that most of the novel epitopes would not have been predicted. Our study emphasizes the importance of using a systematic approach to identify immunodominant CD8(+) T-cell responses and suggests that the epitope-rich regions within NP present a promising target for the T-cell-mediated multi-strain influenza vaccine.
authors: Department of Microbiology and Immunology, University of Melbourne, Royal Parade, Melbourne, Victoria, Australia.
authors: Emma
authors: E
authors: Grant
authors: Chao
authors: C
authors: Wu
authors: Kok-Fei
authors: KF
authors: Chan
authors: Sidonia
authors: S
authors: Eckle
authors: Mandvi
authors: M
authors: Bharadwaj
authors: Quan Ming
authors: QM
authors: Zou
authors: Katherine
authors: K
authors: Kedzierska
authors: Weisan
authors: W
authors: Chen
mesh_terms: D000465:Algorithms; D000483:Alleles; D000595:Amino Acid Sequence; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D017124:Conserved Sequence; D015789:HLA-A2 Antigen / Q000276:immunology; D006801:Humans; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000276:immunology*; D009980:Influenza A virus / Q000276:immunology*; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D011485:Protein Binding / Q000276:immunology; D016601:RNA-Binding Proteins / Q000276:immunology*; D014758:Viral Core Proteins / Q000276:immunology*
chemical_list: D015789:HLA-A2 Antigen; D016056:Immunodominant Epitopes; C048842:NP protein, Influenza A virus; D019590:Nucleocapsid Proteins; D010455:Peptides; D016601:RNA-Binding Proteins; D014758:Viral Core Proteins