Cellular and molecular insights on the regulation of innate immune responses to experimental aspergillosis in chicken and turkey poults

• Published in: Medical mycology (Oxford) Vol. 59; no. 5; pp. 465 - 475
• Main Authors: Vahsen, Tobias, Zapata, Laura, Guabiraba, Rodrigo, Melloul, Elise, Cordonnier, Nathalie, Botterel, Françoise, Guillot, Jacques, Arné, Pascal, Risco-Castillo, Veronica
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 04-05-2021
• Subjects: Animal biology; Life Sciences; Microbiology and Parasitology; Mycology; chicken; cytokines; immune response; turkey; aspergillosis
• ISSN: 1369-3786; 1460-2709; 1365-280X
• DOI: 10.1093/mmy/myaa069

Abstract
Across the world, many commercial poultry flocks and captive birds are threatened by infection with Aspergillus fumigatus. Susceptibility to aspergillosis varies among birds; among galliform birds specifically, morbidity and mortality rates seem to be greater in turkeys than in chickens. Little is known regarding the features of avian immune responses after inhalation of Aspergillus conidia, and to date, scarce information on inflammatory responses during aspergillosis exists. Thus, in the present study, we aimed to improve our understanding of the interactions between A. fumigatus and economically relevant galliform birds in terms of local innate immune responses. Intra-tracheal aerosolization of A. fumigatus conidia in turkey and chicken poults led to more severe clinical signs and lung lesions in turkeys, but leukocyte recovery from lung lavages was higher in chickens at 1dpi only. Interestingly, only chicken CD8+ T lymphocyte proportions increased after infection. Furthermore, the lungs of infected chickens showed an early upregulation of pro-inflammatory cytokines, including IL-1β, IFN-γ and IL-6, whereas in turkeys, most of these cytokines showed a downregulation or a delayed upregulation. These results confirmed the importance of an early pro-inflammatory response to ensure the development of an appropriate anti-fungal immunity to avoid Aspergillus dissemination in the respiratory tract. In conclusion, we show for the first time that differences in local innate immune responses between chickens and turkeys during aspergillosis may determine the outcome of the disease.
Lay Summary
Aspergillus fumigatus infection may cause mortality in poultry, depending on species sensitivity. This study confirms the earlier activation of chickens’ pro-inflammatory effectors to control Aspergillus dissemination, whereas turkeys’ immune response enables the exacerbation of lung lesions.