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lpr mice
Abstracts / Molecular Immunology 45 (2008) 4095–4182
provide conceptual basis for the development of immune desensitization for liposomal drug-induced hypersensitivity reactions and other tachyphylactic CARPA reactions. doi:10.1016/j.molimm.2008.08.171 P173 The alternative pathway of complement alone can mediate collagen antibody-induced arthritis in mice and generate high levels of C5a in vitro Nirmal K. Banda a , Brandt Levitt a , Allyson Wood a , Magdalena Glogowska a , Kazue Takahashi b , Gregory L. Stahl c , William P. Arend a , V. Michael Holers a a
UCDHSC, Aurora, USA Massachusetts General Hospital for Children, Boston, USA c Brigham and Women’s Hospital, Boston, USA b
Collagen (CII) antibody-induced arthritis (CAIA), a model of immune complex arthritis in mice, requires the alternative pathway (AP) of complement. The objectives of these studies were to examine CAIA in mice possessing only the classical pathway (CP) or lectin pathway (LP) and the relative potency of C3 and C5 convertases generated by each pathway. CAIA was induced in C57BL/6 mice by injecting four anti-CII mAb (Arthrogen) IP on day 0 and LPS IP on day 3. Clinical disease activity scores (DAS) were determined daily and quantitative histopathology was performed on mice sacrificed on day 10. Mice possessing only the CP (MBL−/−/fD−/−) or LP (C1q−/−/fD−/−) were resistant to CAIA compared to mice possessing only the AP (MBL−/−/C1q−/−), by both clinical and histological criteria. C3 deposition in the synovium and cartilage was significantly reduced in mice with only the CP (p < 0.0017 and p < 0.05) and LP (p < 0.0001 and p < 0.001) in comparison to wild type (WT) mice. C3 deposition and C5a generation induced by adherent anti-CII mAb in vitro was determined using sera from WT, C4−/−, fB−/−, or MBL−/−, sera from mice possessing only CP, AP or LP, and sera from C5-deficient NOD mice. The levels of C3 deposition were not different using any of these sera, except much lower with LP only sera. In comparison to sera from WT, C4−/−, MBL−/− and AP only mice, C5a generation was reduced by ∼80% using sera from fB−/− and CP only mice, while LP only and NOD mice generated no detectable C5a. The results of our studies show that, in contrast to AP only mice, CP or LP only mice poorly develop CAIA with low levels of C3 deposition in the joints. Adherent anti-CII mAb induce equivalent levels of C3 deposition in vitro using the CP and AP, while C5a generation is lower in CP sera. These results are consistent with a ∼4-fold greater capacity of the AP C5 convertase to generate C5a in this IC model as compared to the CP, while the LP plays a lesser role. doi:10.1016/j.molimm.2008.08.172 P174 Targeted inhibition of the alternative pathway by CR2-fH fusion protein ameliorates progression of renal disease in MRL/lpr mice Hideharu Sekine, Gary Gilkeson, Stephen Tomlinson Medical University of South Carolina, Charleston, USA The complement system appears to play a dual role in the progression of lupus; serving a beneficial role in enhancing the clearance of immune complexes (ICs) and apoptotic cells, while serving a pathogenic role in inducing local inflammation and injury. Therefore, an approach to inhibit complement-mediated
4153
local inflammation without suppressing complement systemically represents an attractive therapeutic strategy. Here, we investigated the therapeutic use of CR2-factor H (fH), a targeted inhibitor specific for the alternative pathway (described in accompanying abstract by Huang et al.). The CR2 moiety binds to C3 activation products deposited at sites of complement activation and thus targets the complement inhibitory fH fusion partner (SCR1–5), a strategy that limits systemic inhibition of complement. Groups of eight MRL/lpr mice (male:female, 4:4) were injected with CR2-fH i.v. for 8 weeks starting after onset of proteinuria at week 15 (0.4 mg weekly or biweekly). Mice were also treated with sCR2 alone (0.25 mg weekly) or with saline. Sera and urine were collected biweekly, and kidneys were collected for histological evaluation at 23 weeks. Compared to controls (saline), female mice treated biweekly with CF2-fH showed significantly reduced urinary albumin excretion, a significant reduction in serum anti-dsDNA Ab levels and a trend toward reduced glomerulonephritis. Mice receiving weekly injections of sCR2 also showed significantly reduced urinary albumin excretion. Although preliminary, the data indicate that targeted inhibition of the alternative complement pathway is an effective treatment for murine lupus. In addition to the potential benefit of avoiding systemic complement inhibition by a targeted approach, there may be important benefits to leaving the classical pathway intact with regard to autoimmunity and the handling of ICs and apoptotic cells. doi:10.1016/j.molimm.2008.08.173 P175 Zymosan, but not LPS, triggers severe and progressive peritoneal injury accompanied by complement activation in a rat peritonitis model initiated by mechanical scraping Masashi Mizuno a , Yasuhiko Ito a , Tomohiro Mizuno b , Claire L. Harris c , B. Paul Morgan c , Natalie Hepburn c , Hayato Nishimura a , Seiichi Matsuo a a
Nagoya University, Nagoya, Japan Meijo University, Nagoya, Japan c Cardiff University, Cardiff, UK b
Fungal or yeast peritonitis is an important complication in peritoneal dialysis (PD) patients and either continuous or recurrent peritonitis may enhance peritoneal damage. Even when the PD catheter is removed in patients with fungal peritonitis, peritoneal fibrosis can sometimes progress and finally evolve into encapsular peritoneal sclerosis (EPS). It is not clear why fungal infections are worse than bacterial in these respects. Zymosan (Z) is a cellwall component of yeast that strongly activates the complement (C) system. Here, we investigated whether either Z or the bacterial product lipopolysaccharide (LPS) augmented peritoneal inflammation in a rat peritonitis model induced by mechanical scraping. Intraperitoneal administration of Z, but not LPS or vehicle, markedly enhanced peritonitis with massive infiltration of cells and deposition of C activation products C3b and membrane attack complex (MAC) on day 5. In rats administered Z and sacrificed on day 18 or 36, the peritoneal inflammation persisted with accumulation of ED-1 positive cells, small deposits of C3b and MAC, increased capillaries in sub-peritoneal tissues. ␣-Smooth muscle actin was strongly expressed on days 5 and 18. When we compared a single administration of Z with daily exposure for 5 days in the rat peritoneal scrape model, the latter clearly caused enhanced peritoneal inflammation with increased peritoneal thickness, inflammatory cell accumulation and C deposition. When systemic complement activity was inhibited using cobra venom factor, peritoneal inflammation was decreased in Z-treated rats. Moreover, intraperitoneal
provide conceptual basis for the development of immune desensitization for liposomal drug-induced hypersensitivity reactions and other tachyphylactic CARPA reactions. doi:10.1016/j.molimm.2008.08.171 P173 The alternative pathway of complement alone can mediate collagen antibody-induced arthritis in mice and generate high levels of C5a in vitro Nirmal K. Banda a , Brandt Levitt a , Allyson Wood a , Magdalena Glogowska a , Kazue Takahashi b , Gregory L. Stahl c , William P. Arend a , V. Michael Holers a a
UCDHSC, Aurora, USA Massachusetts General Hospital for Children, Boston, USA c Brigham and Women’s Hospital, Boston, USA b
Collagen (CII) antibody-induced arthritis (CAIA), a model of immune complex arthritis in mice, requires the alternative pathway (AP) of complement. The objectives of these studies were to examine CAIA in mice possessing only the classical pathway (CP) or lectin pathway (LP) and the relative potency of C3 and C5 convertases generated by each pathway. CAIA was induced in C57BL/6 mice by injecting four anti-CII mAb (Arthrogen) IP on day 0 and LPS IP on day 3. Clinical disease activity scores (DAS) were determined daily and quantitative histopathology was performed on mice sacrificed on day 10. Mice possessing only the CP (MBL−/−/fD−/−) or LP (C1q−/−/fD−/−) were resistant to CAIA compared to mice possessing only the AP (MBL−/−/C1q−/−), by both clinical and histological criteria. C3 deposition in the synovium and cartilage was significantly reduced in mice with only the CP (p < 0.0017 and p < 0.05) and LP (p < 0.0001 and p < 0.001) in comparison to wild type (WT) mice. C3 deposition and C5a generation induced by adherent anti-CII mAb in vitro was determined using sera from WT, C4−/−, fB−/−, or MBL−/−, sera from mice possessing only CP, AP or LP, and sera from C5-deficient NOD mice. The levels of C3 deposition were not different using any of these sera, except much lower with LP only sera. In comparison to sera from WT, C4−/−, MBL−/− and AP only mice, C5a generation was reduced by ∼80% using sera from fB−/− and CP only mice, while LP only and NOD mice generated no detectable C5a. The results of our studies show that, in contrast to AP only mice, CP or LP only mice poorly develop CAIA with low levels of C3 deposition in the joints. Adherent anti-CII mAb induce equivalent levels of C3 deposition in vitro using the CP and AP, while C5a generation is lower in CP sera. These results are consistent with a ∼4-fold greater capacity of the AP C5 convertase to generate C5a in this IC model as compared to the CP, while the LP plays a lesser role. doi:10.1016/j.molimm.2008.08.172 P174 Targeted inhibition of the alternative pathway by CR2-fH fusion protein ameliorates progression of renal disease in MRL/lpr mice Hideharu Sekine, Gary Gilkeson, Stephen Tomlinson Medical University of South Carolina, Charleston, USA The complement system appears to play a dual role in the progression of lupus; serving a beneficial role in enhancing the clearance of immune complexes (ICs) and apoptotic cells, while serving a pathogenic role in inducing local inflammation and injury. Therefore, an approach to inhibit complement-mediated
4153
local inflammation without suppressing complement systemically represents an attractive therapeutic strategy. Here, we investigated the therapeutic use of CR2-factor H (fH), a targeted inhibitor specific for the alternative pathway (described in accompanying abstract by Huang et al.). The CR2 moiety binds to C3 activation products deposited at sites of complement activation and thus targets the complement inhibitory fH fusion partner (SCR1–5), a strategy that limits systemic inhibition of complement. Groups of eight MRL/lpr mice (male:female, 4:4) were injected with CR2-fH i.v. for 8 weeks starting after onset of proteinuria at week 15 (0.4 mg weekly or biweekly). Mice were also treated with sCR2 alone (0.25 mg weekly) or with saline. Sera and urine were collected biweekly, and kidneys were collected for histological evaluation at 23 weeks. Compared to controls (saline), female mice treated biweekly with CF2-fH showed significantly reduced urinary albumin excretion, a significant reduction in serum anti-dsDNA Ab levels and a trend toward reduced glomerulonephritis. Mice receiving weekly injections of sCR2 also showed significantly reduced urinary albumin excretion. Although preliminary, the data indicate that targeted inhibition of the alternative complement pathway is an effective treatment for murine lupus. In addition to the potential benefit of avoiding systemic complement inhibition by a targeted approach, there may be important benefits to leaving the classical pathway intact with regard to autoimmunity and the handling of ICs and apoptotic cells. doi:10.1016/j.molimm.2008.08.173 P175 Zymosan, but not LPS, triggers severe and progressive peritoneal injury accompanied by complement activation in a rat peritonitis model initiated by mechanical scraping Masashi Mizuno a , Yasuhiko Ito a , Tomohiro Mizuno b , Claire L. Harris c , B. Paul Morgan c , Natalie Hepburn c , Hayato Nishimura a , Seiichi Matsuo a a
Nagoya University, Nagoya, Japan Meijo University, Nagoya, Japan c Cardiff University, Cardiff, UK b
Fungal or yeast peritonitis is an important complication in peritoneal dialysis (PD) patients and either continuous or recurrent peritonitis may enhance peritoneal damage. Even when the PD catheter is removed in patients with fungal peritonitis, peritoneal fibrosis can sometimes progress and finally evolve into encapsular peritoneal sclerosis (EPS). It is not clear why fungal infections are worse than bacterial in these respects. Zymosan (Z) is a cellwall component of yeast that strongly activates the complement (C) system. Here, we investigated whether either Z or the bacterial product lipopolysaccharide (LPS) augmented peritoneal inflammation in a rat peritonitis model induced by mechanical scraping. Intraperitoneal administration of Z, but not LPS or vehicle, markedly enhanced peritonitis with massive infiltration of cells and deposition of C activation products C3b and membrane attack complex (MAC) on day 5. In rats administered Z and sacrificed on day 18 or 36, the peritoneal inflammation persisted with accumulation of ED-1 positive cells, small deposits of C3b and MAC, increased capillaries in sub-peritoneal tissues. ␣-Smooth muscle actin was strongly expressed on days 5 and 18. When we compared a single administration of Z with daily exposure for 5 days in the rat peritoneal scrape model, the latter clearly caused enhanced peritoneal inflammation with increased peritoneal thickness, inflammatory cell accumulation and C deposition. When systemic complement activity was inhibited using cobra venom factor, peritoneal inflammation was decreased in Z-treated rats. Moreover, intraperitoneal