CD4+TGFβ+ cells infiltrated the bursa of Fabricius following IBDV infection, and correlated with a delayed viral clearance, but did not correlate with disease severity, or immunosuppression

作者：Salik Nazki, Vishwanatha R. A. P. Reddy, Nitin Uttam Kamble, Jean-Rémy Sadeyen, Munir Iqbal, Shahriar Behboudi, Holly Shelton, Andrew J. Broadbent · 发表于：Frontiers in Immunology · 年份：2023 · DOI：10.3389/fimmu.2023.1197746 · 被引用次数：12 · 研究领域：Parvovirus B19 Infection Studies、Virology and Viral Diseases、Animal Virus Infections Studies

Introduction Infectious Bursal Disease Virus (IBDV) causes immunosuppression in chickens. While B-cell destruction is the main cause of humoral immunosuppression, bursal T cells from IBDV-infected birds have been reported to inhibit the mitogenic response of splenocytes, indicating that some T cell subsets in the infected bursa have immunomodulatory activities. CD4 + CD25 + TGFβ + cells have been recently described in chickens that have immunoregulatory properties and play a role in the pathogenesis of Marek’s Disease Virus. Methods To evaluate if CD4 + CD25 + TGFβ + cells infiltrated the bursa of Fabricius (BF) following IBDV infection, and influenced the outcome of infection, birds were inoculated at either 2 days or 2 weeks of age with vaccine strain (228E), classic field strain (F52/70), or PBS (mock), and bursal cell populations were quantified by flow cytometry. Results Both 228E and F52/70 led to atrophy of the BF, a significant reduction of Bu1 + -B cells, and a significant increase in CD4 + and CD8α + T cells in the BF, but only F52/70 caused suppression of immune responses to a test antigen in younger birds, and clinical signs in older birds. Virus was cleared from the BF more rapidly in younger birds than older birds. An infiltration of CD4 + CD25 + T cells into the BF, and elevated expression of bursal TGFβ-1 + mRNA was observed at all time points following infection, irrespective of the strain or age of the birds, but CD4 + TGFβ + cells and CD4 + CD25 + TGFβ + ce...