Replication of infectious bronchitis virus (IBV) Delmarva (DMV)/1639 variant in primary and secondary lymphoid organs leads to immunosuppression in chickens

Shahnas M Najimudeen; Reham M Abd-Elsalam; Hiruni A Ranaweera; Ishara M Isham; Mohamed S H Hassan; Muhammad Farooq; Mohamed Faizal Abdul-Careem

doi:10.1016/j.virol.2023.109852

Replication of infectious bronchitis virus (IBV) Delmarva (DMV)/1639 variant in primary and secondary lymphoid organs leads to immunosuppression in chickens

Virology. 2023 Oct:587:109852. doi: 10.1016/j.virol.2023.109852. Epub 2023 Jul 28.

Authors

Shahnas M Najimudeen¹, Reham M Abd-Elsalam², Hiruni A Ranaweera¹, Ishara M Isham¹, Mohamed S H Hassan³, Muhammad Farooq¹, Mohamed Faizal Abdul-Careem⁴

Affiliations

¹ Faculty of Veterinary Medicine, University of Calgary, Health Research Innovation Center 2C53, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
² Faculty of Veterinary Medicine, University of Calgary, Health Research Innovation Center 2C53, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada; Faculty of Veterinary Medicine, Cairo University, 12211, Giza, Egypt.
³ Faculty of Veterinary Medicine, University of Calgary, Health Research Innovation Center 2C53, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada; Department of Poultry Diseases, Faculty of Veterinary Medicine, Assiut University, Assiut, 71515, Egypt.
⁴ Faculty of Veterinary Medicine, University of Calgary, Health Research Innovation Center 2C53, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada. Electronic address: faizal.abdulcareem@ucalgary.ca.

PMID: 37531823
DOI: 10.1016/j.virol.2023.109852

Abstract

Infectious bronchitis virus (IBV) that primarily causes respiratory infection in chickens, disseminate to multiple body systems leading to pathology, results in economic losses to poultry industry. IBV replicates in the bursa of Fabricius (BF), Harderian gland (HG), cecal tonsils (CT), and spleen. The objective of this study was to investigate the immunosuppressive effect of IBV Delmarva (DMV/1639) variant in chickens. Specific pathogen free chickens were infected with the IBV DMV/1639 variant while maintaining an age-matched uninfected control group. At predetermined time points, subsets of the infected and control chickens were observed for changes in body weights and pathological changes. The histopathological lesions were observed in the CT and BF, with minimal lesions in the thymus and spleen. The mRNA expression of pro-inflammatory mediators suggested immunomodulation by IBV, favoring viral replication. Further studies are warranted to observe the functional impact of the IBV DMV/1639 variant's replication in immune organs.

Keywords: Bursa of fabricius; Cecal tonsils; Immune suppression; Infectious bronchitis virus; Spleen; Thymus.