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Abstracts / Molecular Imm

rotein (C4BP) and factor H (fH) affect their degradation. Freshlysolated human neutrophils were induced to produce NETs andNA degradation assays and confocal microscopy were used as

ead-out systems. We found that C1q decreased the degradationf NETs by DNase-I, whereas C4BP and fH had no affect. C1q boundo a high extent to the NETs, which possibly explains the obser-ation that C1q protects the NETs from degradation by DNase-I.ET-bound C1q/C1 can trigger complement cascade and we found3b deposits on the NETs incubated with human serum. How theomplement activation and deposition from human sera affectsegradation is currently under investigation. This study brings two

mportant components of the innate immune system together andill broaden the understanding of how deficiencies in the separate

ystems affect, and in some cases, lead to human diseases.

oi:10.1016/j.molimm.2010.05.228

0

AF deficiency is protective during atherosclerosis in apoE defi-ient mice

. Lewis a, Christopher L. Jackson b, Mark J. Perry b, B. Paulorgan a, Timothy R. Hughes a

Cardiff University, Cardiff, UKBristol University, Bristol, UK

Atherosclerosis, the leading cause of death in the westernorld, is a disease driven by chronic inflammation within the

rtery wall. The involvement of complement in atherosclerosisas gradually become evident with human studies showing depo-ition of complement proteins and activation products withinhe atherosclerotic plaque. Data generated from animal studiesave revealed that different pathways and activation productsf complement have conflicting roles within the disease process.ctivation of the terminal pathway appears to be proathero-enic as revealed through the use of apoE mice deficient in6 or the terminal pathway regulator CD59, while the rolef the activation pathways still remains unclear with studiesn C3 deficient mice implying a protective role for C3. Wexamined the role of decay accelerating factor (DAF; CD55), aembrane inhibitor of the C3 convertase, in atherosclerosis by

ackcrossing DAF deficient mice (DAF−/−) onto the apoE defi-ient (apoE−/−) background. Adult male ApoE−/−DAF−/− miceere fed a high fat diet for 12 weeks. Severity of atherosclero-

is was assessed in the brachiocephalic artery and lipid analysisarried out on serum. ApoE−/−/DAF−/− mice had significantlymaller atherosclerotic plaques when compared to apoE−/−ontrols (cross-sectional area 46 �m × 103 �m ± 14 × 103 versus46 �m × 103 �m ± 14 × 103). Triglyceride levels were signifi-antly lower than those present in control animals before2.1 ± 0.1 mmol versus 5.1 ± 0.6 mmol) and after (1.667 ± 0.3 mmolersus 3.6 ± 0.5 mmol) high fat diet. Cholesterol levels after highat feeding were also markedly lower in apoE−/−/DAF−/− miceompared to controls (29.0 ± 1.8 mmol/L versus 38.3 ± 2.5 mmol/L).onversely, percentage body fat was raised in apoE−/−/DAF−/−

ice compared to controls (28.63 ± 4.2% versus 19.5 ± 1.8%). We

uggest that these changes are a direct consequence of complementysregulation and provide evidence in support of this hypothesis.

oi:10.1016/j.molimm.2010.05.229

gy 47 (2010) 2198–2294 2275

51

The onset of reperfusion injury: Deposition of antibodies andcomplement in viable myocardium in a porcine model of acutecoronary syndrome

Pranitha Kamat a, Anne Broillet b, Alexandre Helbert b, ThierryBettinger b, Francois Tranquart b, Michel Schneider b, RobertRieben a

a University of Bern, Department of Clinical Research, Bern, Switzerlandb Bracco Research SA, Geneva, Switzerland

Background: Recognition of ischemia-induced neoepitopes byIgM, followed by complement activation, was proposed as patho-physiological mechanism in reperfusion injury. The respective dataare from mouse models with considerable reperfusion-inducedtissue necrosis. We now assessed the role of antibodies and com-plement in a porcine model of acute coronary syndrome withshort term ischemia and minimal reperfusion-induced myocardialnecrosis.

Method: Six piglets of 30 kg were used to induce coronary occlu-sion by a balloon catheter for 20 min, followed by 6 h of reperfusion.The myocardial ischemic area at risk (AAR) was demarcated byEvan’s Blue. Triphenyl tetrazolium chloride incubation was usedto discriminate between vital and necrotic parts. Deposition ofIgM, IgG and C3b/c were detected by immunofluorescence. Con-trast echocardiography with antibody-coated microbubbles wasused to non-invasively assess P-selection expression within themyocardium and compared with Immunohistochemistry on paraf-fin sections.

Results: In this short term coronary occlusion model, noreperfusion-induced myocardial necrosis was observed and only2 out of 6 animals showed increased troponin-I. However, deposi-tion of IgG (P = 0.035) and C3b/c (P = 0.014) was significantly higherin the AAR than in the non-ischemic myocardium. IgM depositionwas also apparently higher, but the difference was not significant.P-selectin expression could be observed specifically within the AARby contrast echocardiography and correlated with immunohisto-chemical detection.

Discussion: The observed deposition of IgG, IgM and C3b/c withinthe AAR, in the absence of tissue necrosis, suggests that indeed nat-ural antibodies and complement may be essential players in theonset of ischemia/reperfusion injury. The presence of these mark-ers, together with the expression of P-selectin, can therefore beused to identify even short term myocardial ischemia up to severalhours after the ischemic event.

doi:10.1016/j.molimm.2010.05.230

52

Complement activation in preterm delivery in mice

Juan M. Gonzalez a, Claus V. Franzke b, Roberto Romero a, Guiller-mina Girardi c

a Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Mary-land and Detroit, MI, USAb Molecular Dermatology,University of Freiburg, Germanyc York College, CUNY, New York, NY, USA

Preterm labor/delivery (PTD) is the leading cause of perinatalmorbidity and mortality worldwide. It is the leading identifiablecause of cerebral palsy and it costs $26 billion per year in the

U.S. alone. Infection/inflammation is the only mechanism of dis-ease which has been causally linked to spontaneous preterm labor.The innate immune system plays a key role in parturition; there-fore we decided to study the role of complement activation in the