Titel (eng)

Aerosol vaccination of chicken pullets with irradiated avian pathogenic Escherichia coli induces a local immunostimulatory effect

Autor*in

Sina Bagheri   University of Veterinary Medicine Vienna

Dieter Liebhart   University of Veterinary Medicine Vienna

Michael Hess   University of Veterinary Medicine Vienna

Claudia Hess   University of Veterinary Medicine Vienna

Manolis Lyrakis   University of Veterinary Medicine Vienna

Giovanni Cattoli   International Atomic Energy Agency

Richard Thiga Kangethe   International Atomic Energy Agency

Viskam Wijewardana   International Atomic Energy Agency

Simon Könnyü   University of Veterinary Medicine Vienna

Mohamed Kamal Abdelhamid   University of Veterinary Medicine Vienna

Taniya Mitra   University of Veterinary Medicine Vienna

Surya Paudel   University of Veterinary Medicine Vienna

Verlag

Frontiers Media Sa

Beschreibung (eng)

The present study investigated the expression of cytokines and cellular changes in chickens following vaccination with irradiated avian pathogenic Escherichia coli (APEC) and/or challenge. Four groups of 11-week-old pullets, each consisting of 16 birds were kept separately in isolators before they were sham inoculated (N), challenged only (C), vaccinated (V) or vaccinated and challenged (V+C). Vaccination was performed using irradiated APEC applied via aerosol. For challenge, the homologous strain was administered intratracheally. Birds were sacrificed on 3, 7, 14 and 21 days post challenge (dpc) to examine lesions, organ to body weight ratios and bacterial colonization. Lung and spleen were sampled for investigating gene expression of cytokines mediating inflammation by RT-qPCR and changes in the phenotype of subsets of mononuclear cells by flow cytometry. After re-stimulation of immune cells by co-cultivation with the pathogen, APEC-specific IFN-γ producing cells were determined. Challenged only birds showed more severe pathological and histopathological lesions, a higher probability of bacterial re-isolation and higher organ to body weight ratios compared to vaccinated and challenged birds. In the lung, an upregulation of IL-1β and IL-6 following vaccination and/or challenge at 3 dpc was observed, whereas in the spleen IL-1β was elevated. Changes were observed in macrophages and TCR-γδ+ cells within 7 dpc in spleen and lung of challenged birds. Furthermore, an increase of CD4+ cells in spleen and a rise of Bu-1+ cells in lung were present in vaccinated and challenged birds at 3 dpc. APEC re-stimulated lung and spleen mononuclear cells from only challenged pullets showed a significant increase of IFN-γ+CD8α+ and IFN-γ+TCR-γδ+ cells. Vaccinated and challenged chickens responded with a significant increase of IFN-γ+CD8α+ T cells in the lung and IFN-γ+TCR-γδ+ cells in the spleen. Re-stimulation of lung mononuclear cells from vaccinated birds resulted in a significant increase of both IFN-γ+CD8α+ and IFN-γ+TCR-γδ+ cells. In conclusion, vaccination with irradiated APEC caused enhanced pro-inflammatory response as well as the production of APEC-specific IFN-γ-producing γδ and CD8α T cells, which underlines the immunostimulatory effect of the vaccine in the lung. Hence, our study provides insights into the underlying immune mechanisms that account for the defense against APEC.

Sprache des Objekts

Englisch

Datum

2023

Rechte

Dieses Werk bzw. dieser Inhalt steht unter einer
CC BY 4.0 - Creative Commons Namensnennung 4.0 International Lizenz.

CC BY 4.0 International

http://creativecommons.org/licenses/by/4.0/

Klassifikation

Colibacillosis; Virulence; Responses; Broilers; Poultry; Spray; Cells; Pcr

Mitglied in der/den Collection(s) (1)