title: Influenza A Virus Infection in Pigs Attracts Multifunctional and Cross-Reactive T Cells to the Lung.
abstract: Pigs are natural hosts for influenza A viruses and play a critical role in influenza epidemiology. However, little is known about their influenza-evoked T-cell response. We performed a thorough analysis of both the local and systemic T-cell response in influenza virus-infected pigs, addressing kinetics and phenotype as well as multifunctionality (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α], and interleukin-2 [IL-2]) and cross-reactivity. A total of 31 pigs were intratracheally infected with an H1N2 swine influenza A virus (FLUAVsw) and consecutively euthanized. Lungs, tracheobronchial lymph nodes, and blood were sampled during the first 15 days postinfection (p.i.) and at 6 weeks p.i. Ex vivo flow cytometry of lung lymphocytes revealed an increase in proliferating (Ki-67(+)) CD8(+) T cells with an early effector phenotype (perforin(+) CD27(+)) at day 6 p.i. Low frequencies of influenza virus-specific IFN-γ-producing CD4(+) and CD8(+) T cells could be detected in the lung as early as 4 days p.i. On consecutive days, influenza virus-specific CD4(+) and CD8(+) T cells produced mainly IFN-γ and/or TNF-α, reaching peak frequencies around day 9 p.i., which were up to 30-fold higher in the lung than in tracheobronchial lymph nodes or blood. At 6 weeks p.i., CD4(+) and CD8(+) memory T cells had accumulated in lung tissue. These cells showed diverse cytokine profiles and in vitro reactivity against heterologous influenza virus strains, all of which supports their potential to combat heterologous influenza virus infections in pigs.
  
  
  
  Pigs not only are a suitable large-animal model for human influenza virus infection and vaccine development but also play a central role in the emergence of new pandemic strains. Although promising candidate universal vaccines are tested in pigs and local T cells are the major correlate of heterologous control, detailed and targeted analyses of T-cell responses at the site of infection are scarce. With the present study, we provide the first detailed characterization of magnitude, kinetics, and phenotype of specific T cells recruited to the lungs of influenza virus-infected pigs, and we could demonstrate multifunctionality, cross-reactivity, and memory formation of these cells. This, and ensuing work in the pig, will strengthen the position of this species as a large-animal model for human influenza virus infection and will immediately benefit vaccine development for improved control of influenza virus infections in pigs.
authors: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
authors: Stephanie C
authors: SC
authors: Talker
authors: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
authors: Maria
authors: M
authors: Stadler
authors: University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.
authors: Hanna C
authors: HC
authors: Koinig
authors: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
authors: Kerstin H
authors: KH
authors: Mair
authors: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
authors: Irene M
authors: IM
authors: Rodríguez-Gómez
authors: University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.
authors: Robert
authors: R
authors: Graage
authors: Department of Virology and Antiviral Therapy, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
authors: Roland
authors: R
authors: Zell
authors: Viral Vaccines, Business Unit Animal Health, IDT Biologika GmbH, Dessau-Rosslau, Germany.
authors: Ralf
authors: R
authors: Dürrwald
authors: Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany.
authors: Elke
authors: E
authors: Starick
authors: Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany.
authors: Timm
authors: T
authors: Harder
authors: Institute of Pathology and Forensic Veterinary Medicine, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
authors: Herbert
authors: H
authors: Weissenböck
authors: Institute of Virology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
authors: Benjamin
authors: B
authors: Lamp
authors: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
authors: Sabine E
authors: SE
authors: Hammer
authors: University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.
authors: Andrea
authors: A
authors: Ladinig
authors: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
authors: Armin
authors: A
authors: Saalmüller
authors: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria wilhelm.gerner@vetmeduni.ac.at.
authors: Wilhelm
authors: W
authors: Gerner
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003429:Cross Reactions / Q000276:immunology*; D057221:Influenza A Virus, H1N2 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D008168:Lung / Q000276:immunology* / Q000821:virology; D009976:Orthomyxoviridae Infections / Q000276:immunology*; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000821:virology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D007252:Influenza Vaccines; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma