Dynamic alterations in T-lymphocyte subsets assessed by flow cytometry in chickens following exposure to infectious bursal disease virus: A systematic review

• Published in: Developmental and comparative immunology 2025-01, Vol.162, p.105280, Article 105280
• Main Authors: Pedrazzoli, Sara, Graziosi, Giulia, Salaroli, Roberta, Catelli, Elena, Lupini, Caterina
• Format: Article
• Language: English
• Subjects: Animals; B-lymphocytes; Birnaviridae Infections - immunology; Birnaviridae Infections - veterinary; Birnaviridae Infections - virology; bursa of Fabricius; Bursa of Fabricius - immunology; Bursa of Fabricius - virology; CD4-positive T-lymphocytes; CD4-Positive T-Lymphocytes - immunology; CD8-positive T-lymphocytes; CD8-Positive T-Lymphocytes - immunology; Chicken; chickens; Chickens - immunology; Chickens - virology; Flow Cytometry; Immune response; immunosuppression; Infectious bursal disease virus; Infectious bursal disease virus (IBDV); Infectious bursal disease virus - immunology; pathogenesis; pathogens; Poultry Diseases - immunology; Poultry Diseases - virology; spleen; Spleen - immunology; Spleen - virology; Systematic review; T-cell; T-Lymphocyte Subsets - immunology
• ISSN: 0145-305X; 1879-0089; 1879-0089
• DOI: 10.1016/j.dci.2024.105280

Infectious bursal disease virus (IBDV) is a significant pathogen in poultry, causing acute immunosuppressive disease in young chickens. While B-lymphocyte involvement in IBDV pathogenesis is known, the role of T-cells is incompletely understood. This systematic review presents the alterations in chicken T-lymphocyte subsets after IBDV exposure, assessed by flow cytometry analysis. Four databases were queried for identifying eligible studies focused on experimental infections measuring T-lymphocyte changes in the bursa of Fabricius, spleen, thymus, and peripheral blood mononuclear cells. Of 488 studies found, 25 met the pre-established criteria and were included in the qualitative synthesis of results. Most studies analysed T-lymphocyte responses during the acute phase of IBDV infection, primarily focusing on CD4+ and CD8+ T-cells. Other subsets, such as γδ T-cells and double-positive CD4+CD8+ T-cells, were less frequently investigated. An increase in T-lymphocytes was noted in the bursa of Fabricius, suggesting their active role in viral clearance. In the spleen, CD4+ T-cells commonly increased, while CD8+ responses varied among studies. Increased levels in T-cells were also noted during the chronic infection in the bursa of Fabricius, possibly due to persistent viral antigens. Overall, variations in flow cytometry methods and T-cell output reporting were noted among studies. Based on the data collected, further investigation into diverse T-cell subpopulations beyond CD4+ and CD8+ is needed, as well as the standardization of flow cytometry assays in chickens. •Most of the studies evaluated T-cell changes in the BF, finding a general increase during the acute phase of infection.•Limited number of studies available for the chronic phase in the BF. Findings suggest persistently high levels of T-cells.•Recent studies are focusing on characterizing T-cell subsets during IBDV infection.•Methodological standardization in T-cell labelling is needed for cross-study comparisons.