110. Neutralizing the IL-7Ra (CD127) limits injury in experimental anti-MPO glomerulonephritis
Creators: name: Alikhan1, Maliha
name: Kishimoto1, Kazuya
name: Juli Jaw1, 2
name: Limy Wong1
name: A Richard Kitching1, 2
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Background:</strong> Human data suggests that signaling through the IL-7Rα (CD127) may be important in ANCA-associated glomerulonephritis. These studies use a model of glomerulonephritis mediated by anti-MPO cellular autoimmunity to examine the presence and the phenotype of IL-7Rα<sup>+</sup> (CD127<sup>+</sup>) and IL-7Rα<sub>¯</sub> T cells in the kidney and the function of IL-7Rα in murine cell mediated anti-MPO glomerulonephritis (GN). <strong>Methods</strong>: Experimental anti-MPO glomerulonephritis was induced by immunizing mice with 20ug rMPO in FCA day 0 and 20ug rMPO in FIA on day 7. On day 17, low dose sheep anti-mouse anti-basement membrane (BM) globulin was administered to transiently recruit neutrophils to glomeruli, lodging MPO there and allowing T cell recognition of MPO as the autoantigen. Experiments ended on day 21. Leukocyte accumulation was examined by flow cytometry and immunostaining, injury by histology and albuminuria. CD127<sup>+</sup>PD-1<sub>¯</sub> and CD127<sub>¯</sub>PD-1<sup>+</sup> CD4<sup>+</sup> and CD8<sup>+</sup> T cells from kidneys of mice with anti-MPO GN were isolated by FACS, total RNA was extracted from each cell population and whole transcriptomic profiling was performed using next-generation sequencing (Illumina NextSeq550). Differentially expressed genes were identified by linear modelling and an empirical Bayes method (Degust webtool, Victorian Bioinformatics Consortium) with an Fthreshold of 0.05 as indicated to determine significance. Gene set enrichment analysis (GSEA, Broad Institute) was performed to assess whether specific biological pathways or signatures were significantly enriched between different cell populations. The IL-7Rα was neutralized by administering non-depleting anti-IL-7Rα antibodies (0.5mg, alternate days). <strong>Results:</strong> Control ovalbumin-immunized mice given anti-BM globulin developed minimal renal injury, while MPO-immunised mice given anti-BM globulin developed albuminuria, with focal and segmental glomerular lesions. Numbers of intrarenal CD4+ and CD8+ T cells that were either CD127<sup>+</sup> or CD127<sub>¯</sub>PD-1<sup>+</sup> were increased in mice with anti-MPO GN compared with control OVA immunized mice receiving anti-BM globulin. Proportions of these cells within their respective CD4<sup>+</sup> or CD8<sup>+</sup> subset remained similar. In mice with anti-MPO GN, there were 2,541 and 1,664 genes differentially expressed between intrarenal CD127<sub>¯</sub>PD-1<sup>+</sup> and intrarenal CD127<sup>+</sup>PD-1<sub>¯</sub> CD8<sup>+</sup> and CD4<sup>+ </sup>T cells respectively, including <em>Il7r </em>and <em>Pdcd1</em> (PD-1). There was a substantial overlap of the differentially expressed genes between CD8<sup>+</sup> and CD4<sup>+</sup> T cells. Both the CD127<sub>¯</sub>PD-1<sup>+</sup> CD8<sup>+</sup> and CD4<sup>+</sup> T cells were enriched for previously described T cell exhaustion signatures (Figure 1), which predict prognosis in autoimmune disease and viral infection. As CD127<sub>¯</sub> (IL-7Rα<sub>¯</sub>) cells are not likely to be major contributors to injury, the IL-7Rα (CD127) was neutralised in the effector phase of disease after the induction of anti-MPO autoimmunity (commencing day 16). Compared to control IgG, anti-IL-7Rα antibodies limited glomerular and interstitial injury, reduced albuminuria and reduced the numbers of glomerular and interstitial CD4+ and CD8+ T cells, and macrophages. This was associated with reduced intrarenal chemokine and cytokine expression (<em>Cxcl10</em>, <em>Ccl20</em> and <em>Ccl2</em>, <em>Il6</em> and <em>Tnf</em>). <strong>Conclusions:</strong> Both activated and exhausted CD4+ and CD8+ cells are present within kidneys in murine anti-MPO GN. In this model, neutralising activated T cells via the IL-7Rα (CD127) limits intrarenal inflammation and disease. <strong>Disclosures:</strong> None. <strong>Figure 1:</strong> Gene set enrichment analysis in sorted intrarenal T cells from mice with anti-MPO GN.