Publications by authors named "Joshua D K Ooi"

2 Publications

  • Page 1 of 1

Anti-neutrophil cytoplasmic antibodies and effector CD4+ cells play nonredundant roles in anti-myeloperoxidase crescentic glomerulonephritis.

J Am Soc Nephrol 2006 Jul 12;17(7):1940-9. Epub 2006 Jun 12.

Centre for Inflammatory Diseases, Monash University Department of Medicine, Monash Medical Centre, Clayton, VIC 3168, Australia.

Most humans with microscopic polyarteritis and anti-myeloperoxidase (anti-MPO), anti-neutrophil cytoplasmic antibodies (ANCA) develop "pauci-immune" crescentic glomerulonephritis. For dissection of the roles of ANCA and cell-mediated effectors in microscopic polyarteritis, experimental autoimmune anti-MPO glomerulonephritis was induced by immunizing C57BL/6 mice with human MPO. Autoimmunity to mouse MPO (ANCA and CD4+ cell reactivity) was induced. Challenge with anti-glomerular basement membrane globulin resulted in accumulation of neutrophils, CD4+ cells and macrophages, and significant numbers of crescentic glomeruli compared with similarly challenged control-immunized mice. MPO-deficient (Mpo(-/-)) mice immunized with MPO developed similar immune responses to MPO but failed to recruit effector cells to glomeruli or develop significant crescent formation, suggesting that MPO is acting as a planted glomerular autoantigen. Effector CD4+ cell depletion in this model attenuated crescentic glomerulonephritis and effector cell influx without altering ANCA titers. However, B cell-deficient mice, with no ANCA, still developed severe crescentic glomerulonephritis with accumulation of effector cells. Intravital microscopy studies demonstrated that passive transfer of sera from MPO-immunized Mpo(-/-) mice to LPS-primed mice rapidly induced glomerular neutrophil accumulation and release of MPO. These studies provide in vivo evidence in a relevant vascular bed for both humoral and cellular anti-MPO responses as key inducers of injury. ANCA induces glomerular neutrophil infiltration and MPO deposition. Subsequently, anti-MPO CD4+ cells recognize MPO as a planted glomerular antigen and act with macrophages to amplify severe glomerular injury.
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http://dx.doi.org/10.1681/ASN.2006020108DOI Listing
July 2006

The isolation and purification of biologically active recombinant and native autoantigens for the study of autoimmune disease.

J Immunol Methods 2006 Jan 9;308(1-2):167-78. Epub 2005 Dec 9.

Centre for Inflammatory Diseases, Monash University Department of Medicine, Level 5 Block E, Monash Medical Centre, 246 Clayton Rd., Clayton, 3168 Victoria, Australia.

The expression of recombinant, biologically active mouse myeloperoxidase (MPD) and the recombinant non-collagenous (NC1) domain of mouse collagen alpha 3 Type IV was achieved for the first time in Sf21 cells (Spodoptera frugiperda ovarian insect cells) using a baculovirus expression system. Following purification, the proteins were identified by reducing and non-reducing SDS-PAGE electrophoresis. Recombinant mouse MPO has a molecular weight of approximately 90 kDa and mouse alpha3(IV)NC1 approximately 32 kDa. In addition, milligram quantities of native mouse myeloperoxidase were purified from 32Dcl3 cells. Both native and recombinant myeloperoxidase were biologically active. This study also demonstrated that the immunization of myeloperoxidase deficient (Mpo-/-) mice with purified recombinant mouse myeloperoxidase induced a significant antibody response to native myeloperoxidase.
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http://dx.doi.org/10.1016/j.jim.2005.10.011DOI Listing
January 2006