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Selected Publication:

Type of publication: PhD Thesis
Type of document:

Year: 2015

Authors: Koinig, Hanna

Title: Analysis of the porcine cellular immune response against porcine circovirus type 2 and swine Influenza A virus.

Source: PhD-Arbeit, Vet. Med. Univ. Wien, pp. 77.


Authors Vetmeduni Vienna:

Koinig Hanna

Advisor(s):
Saalmüller Armin

Reviewer(s):
Ritzmann Mathias

Vetmed Research Units:
Institute of Immunology


Awards:

  • Staatspreis des Wissenschaftsministeriums für Dissertationen und PhD-Arbeiten.

  • Graduation date: 27.11.15


    Abstract:
    Porcine circovirus type 2 (PCV2) and swine influenza A virus (FLUAVsw) are two of the major viral pathogens threating modern swine production. PCV2 and its associated diseases lead to severe economic losses and novel FLUAVsw reassortants additionally bare the risk of zoonotic potential. This PhD project aimed at investigating the porcine immune response against PCV2 and FLUAVsw with a strong focus on cell-mediated immunity. To address this issue, two controlled infection experiments were conducted. During the PCV2 vaccination/ infection trail, piglets from a conventional farm were vaccinated with a commercial PCV2 subunit vaccine (n=6) or were infected with a PCV2a isolate (n=6). Six piglets were vaccinated and consequently infected and six piglets served as negative control animals. In the second experiment, six seronegative pigs were infected twice with a FLUAVsw H1N2 isolate. Three animals represented the non-infected control group. To analyse the humoral immune response against PCV2 and FLUAVsw, serum samples, taken on regular basis throughout both animal experiments, were investigated for PCV2-specific antibodies and FLUAVsw-specific neutralizing antibodies, respectively. For an in-depth investigation of anti-viral CD4+ and CD8β + T-cell responses peripheral blood mononuclear cells (PBMC) were isolated and analysed by multicolour flow cytometry (FCM). PCV2 vaccination did not induce stable antibody titres in vaccinated animals. Nevertheless, all vaccinated animals were protected against viremia. On the contrary, IFN-γ/ TNF-α co-producing CD4+ T cells with a phenotype of central and effector memory T cells were detected in all pigs after vaccination as well as infection, suggesting that they might contribute to protection. Appearance of these bi-functional T cells coincided with an isotype switch from IgM to IgG in infected animals. Therefore, it is conceivable that IFNγ + TNFα +CD4+ T cells have a helper function for antibody production. This finding further corroborates the hypothesis that they are involved in a protective immune response after PCV2 vaccination. In FLUAVsw infected animals virus-neutralizing antibodies were detected starting from one week post primary infection. Neutralizing antibodies most probably mediated protection against homologous secondary infection. Multi-functional CD4+ T cells, which simultaneously produced IL-2, IFN-γ and TNF-α, were induced after FLUAVsw infection. Central and effector memory T cells were present among this subpopulation of multi-functional CD4+ T cells. On per cell level, higher quantities of IFN-γ and TNF-α were found in double or triple cytokine producing T cells than single cytokine producers. For CD8β + T cells antigen-specific proliferation, cytokine production and expression of the degranulation marker CD107a were analysed. The majority of FLUAVsw-specific CD8β + T cells were multi-functional and performed two or more functions. CD4+ as well as CD8β + multifunctional T cells seem to contribute to a protective immune response against FLUAVsw. It is conceivable that FLUAVsw-specific multi-functional T cells are important for protection against infections with heterologous FLUAVsw strains, but this needs further investigation. In summary, our results provide in-depth insight into the cellular immune response against PCV2 and FLUAVsw. Detailed understanding of the porcine immune response is crucial for design of new vaccines. Since PCV2 vaccines do not induce stable antibody titres in vaccinated animals and protection against heterologous FLUAVsw strains is facilitated by virus-specific T cells, which may target more conserved viral proteins, novel PCV2 and FLUAVsw vaccines should also address the induction of an efficacious T-cell response. The results of this PhD project might help to create new T-cell based vaccines and thereby assist to combat and control continuously changing viruses.


    Publication(s) resulting from University thesis:

    Talker, SC; Koinig, HC; Stadler, M; Graage, R; Klingler, E; Ladinig, A; Mair, KH; Hammer, SE; Weissenböck, H; Dürrwald, R; Ritzmann, M; Saalmüller, A; Gerner, W (2015): Magnitude and kinetics of multifunctional CD4+ and CD8β+ T cells in pigs infected with swine influenza A virus. Vet Res. 2015; 46:52
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    Koinig, HC; Talker, SC; Stadler, M; Ladinig, A; Graage, R; Ritzmann, M; Hennig-Pauka, I; Gerner, W; Saalmüller, A (2015): PCV2 vaccination induces IFN-γ/TNF-α co-producing T cells with a potential role in protection. Vet Res. 2015; 46:20
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