Exacerbation of spontaneous autoimmune nephritis following regulatory T cell depletion in B cell lymphoma 2‐interacting mediator knock‐out mice

• Published in: Clinical and experimental immunology Vol. 188; no. 2; pp. 195 - 207
• Main Authors: Wang, Y. M., Zhang, G. Y., Wang, Y., Hu, M., Zhou, J. J., Sawyer, A., Cao, Q., Zheng, G., Lee, V. W. S., Harris, D. C. H., Alexander, S. I.
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01-05-2017; John Wiley and Sons Inc
• Subjects: Animals; Autoimmune Diseases - immunology; Autoimmune Diseases - pathology; B cell lymphoma (Bcl) 2; Bcl-2-Like Protein 11 - deficiency; Bcl-2-Like Protein 11 - genetics; Bim knock‐out mice; Cytokines - blood; Disease Models, Animal; Disease Progression; Genes; Glomerulonephritis - immunology; Glomerulonephritis - pathology; Glomerulonephritis - physiopathology; Interleukin-10 - blood; Interleukin-6 - blood; Kidney - immunology; Kidney - pathology; Kidney - physiopathology; Kidney diseases; Lymphocyte Depletion; Lymphoma; Mice; Mice, Knockout; Original; Proteinuria; regulatory T cells; Rodents; spontaneous autoimmune glomerulonephritis; T-Lymphocytes, Regulatory - immunology; Tumor necrosis factor-TNF; regulatory T cells; spontaneous autoimmune glomerulonephritis; Bim knock-out mice; B cell lymphoma (Bcl) 2
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1111/cei.12937

Summary
Regulatory T cells (Tregs) have been recognized as central mediators for maintaining peripheral tolerance and limiting autoimmune diseases. The loss of Tregs or their function has been associated with exacerbation of autoimmune disease. However, the temporary loss of Tregs in the chronic spontaneous disease model has not been investigated. In this study, we evaluated the role of Tregs in a novel chronic spontaneous glomerulonephritis model of B cell lymphoma 2‐interacting mediator (Bim) knock‐out mice by transient depleting Tregs. Bim is a pro‐apoptotic member of the B cell lymphoma 2 (Bcl‐2) family. Bim knock‐out (Bim–/–) mice fail to delete autoreactive T cells in thymus, leading to chronic spontaneous autoimmune kidney disease. We found that Treg depletion in Bim–/– mice exacerbated the kidney injury with increased proteinuria, impaired kidney function, weight loss and greater histological injury compared with wild‐type mice. There was a significant increase in interstitial infiltrate of inflammatory cells, antibody deposition and tubular damage. Furthermore, the serum levels of cytokines interleukin (IL)−2, IL‐4, IL‐6, IL‐10, IL‐17α, interferon (IFN)‐γ and tumour necrosis factor (TNF)‐α were increased significantly after Treg depletion in Bim–/– mice. This study demonstrates that transient depletion of Tregs leads to enhanced self‐reactive T effector cell function followed by exacerbation of kidney disease in the chronic spontaneous kidney disease model of Bim‐deficient mice.
Temporary depletion of Tregs in a glomerulonephritis prone Bim‐/‐ mice using the anti‐CD25 mAb PC61 leads to rapid progression of glomerulonephritis and broad systemic immune activation. This suggests that in immune prone individuals temporary loss of Tregs may be a trigger for activation and progression of autoimmune disease.