title: A mutation in the HLA-B*2705-restricted NP383-391 epitope affects the human influenza A virus-specific cytotoxic T-lymphocyte response in vitro.
abstract: Viruses can exploit a variety of strategies to evade immune surveillance by cytotoxic T lymphocytes (CTL), including the acquisition of mutations in or adjacent to CTL epitopes. Recently, an amino acid substitution (R384G) in an HLA-B*2705-restricted CTL epitope in the influenza A virus nucleoprotein (nucleoprotein containing residues 383 to 391 [NP(383-391)]; SRYWAIRTR, where R is the residue that was mutated) was associated with escape from CTL-mediated immunity. The effect of this mutation on the in vitro influenza A virus-specific CTL response was studied. To this end, two influenza A viruses, one with and one without the NP(383-391) epitope, were constructed by reverse genetics and designated influenza viruses A/NL/94-384R and A/NL/94-384G, respectively. The absence of the HLA-B*2705-restricted CTL epitope in influenza virus A/NL/94-384G was confirmed by using (51)Cr release assays with a T-cell clone specific for the NP(383-391) epitope. In addition, peripheral blood mononuclear cells (PBMC) stimulated with influenza virus A/NL/94-384G failed to recognize HLA-B*2705-positive target cells pulsed with the original NP(383-391) peptide. The proportion of virus-specific CD8+ gamma interferon (IFN-gamma)-positive T cells in in vitro-stimulated PBMC was determined by intracellular IFN-gamma staining after restimulation with virus-infected autologous B-lymphoblastoid cell lines and C1R cell lines expressing only HLA-B*2705. The proportion of virus-specific CD8+ T cells was lower in PBMC stimulated in vitro with influenza virus A/NL/94-384G obtained from several HLA-B*2705-positive donors than in PBMC stimulated with influenza virus A/NL/94-384R. This finding indicated that amino acid variations in CTL epitopes can affect the virus-specific CTL response and that the NP(383-391) epitope is the most important HLA-B*2705-restricted epitope in the nucleoprotein of influenza A viruses.
authors.affiliation: Institute of Virology, Erasmus Medical Center, 3000 DR Rotterdam, The Netherlands.
authors.forename: E G M
authors.initials: EG
authors.lastname: Berkhoff
authors.forename: A C M
authors.initials: AC
authors.lastname: Boon
authors.forename: N J
authors.initials: NJ
authors.lastname: Nieuwkoop
authors.forename: R A M
authors.initials: RA
authors.lastname: Fouchier
authors.forename: K
authors.initials: K
authors.lastname: Sintnicolaas
authors.forename: A D M E
authors.initials: AD
authors.lastname: Osterhaus
authors.forename: G F
authors.initials: GF
authors.lastname: Rimmelzwaan
mesh_terms: D000818:Animals; D004285:Dogs; D018984:Epitopes, T-Lymphocyte; D015235:HLA-B Antigens / Q000502:physiology*; D015796:HLA-B27 Antigen; D006801:Humans; D016056:Immunodominant Epitopes; D009980:Influenza A virus / Q000276:immunology*; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology*; D016601:RNA-Binding Proteins; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014758:Viral Core Proteins / Q000276:immunology*
chemical_list: D018984:Epitopes, T-Lymphocyte; D015235:HLA-B Antigens; C464936:HLA-B*27:05 antigen; D015796:HLA-B27 Antigen; D016056:Immunodominant Epitopes; C048842:NP protein, Influenza A virus; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D010446:Peptide Fragments; D016601:RNA-Binding Proteins; D014758:Viral Core Proteins