2274 Abstracts / Molecular Immunology 47 (2010) 2198–2294 was analyzed by hemolytic assay. By 24 h, double knockouts demonstrated paralysis and required euthanasia. In contrast, the mDaf1-/-, mCD59ab-/-, and C57BL/6 mice showed no decrease in strength or slight weakness. Complement deposition was inter- nalized within the muscle fiber in the double knockout mice and the serum complement content was depleted. At 60 h, the other groups demonstrated weakness with mDaf1-/- group showed the greatest severity. After 60 h, the junctions from mDaf1-/- had the greatest membrane attack complex deposition. Intrinsic comple- ment inhibitors moderate the destruction of the neuromuscular junction in EMG and DAF appears to be most important in protec- tion of the junction from damage. doi:10.1016/j.molimm.2010.05.225 48 The contribution of the component C5 in fatty liver disease: A murine model Lorena Bavia, Lourdes Isaac Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil The innate immune system plays a key role in development of Alcoholic Fatty Liver (AFL) and Non-Alcoholic Fatty Liver (NAFL) dis- ease. The complement system leads to an important inflammatory response convincingly linked to pathogenesis of these diseases. It has been suggested that the anaphylatoxins C3a and C5a partici- pate in the process of liver regeneration subsequent to toxic injury. On the other hand, studies in mice fed on ethanol diets have indi- cated that C3 contributes to triglyceride (TG) accumulation and C5 to injury and inflammation in liver. Therefore, we investigated the contribution of C5 to the establishment and maintenance of AFL and NAFL using two different mouse strains. Eight to twelve-week- old male C57Bl/6 (C5 sufficient) and A/J (C5 deficient) mice were allowed free access to a modified Liber-DeCarli diet (Bykov et al., 2004). These mice were fed with ethanol, glucose or maltose dex- trin (this one as a pair-fed control), containing diets for 6, 8 or 10 weeks. Plasma aminotransferase measurements, histopathological analysis, hepatic and plasmatic TG determinations and quantifica- tion of plasma and liver TNF-alpha, IL-6, IL-1beta, IL-10, and IL-12 were performed. We have identified differences between C57Bl/6 and A/J background. Although C57Bl/6 and A/J present fatty liver after 6, 8 and 10 weeks fed ethanol diet, A/J seems to be more resistant in develop steatosis. Surprisingly, C57Bl/6 mice present exacerbated accumulation of hepatic lipids while A/J mice appear to be resistant to liver lipid accumulation after feeding with a glu- cose diet for 10 weeks. Our study suggests the involvement of the complement system, especially the component C5, in the develop- ment of inflammation and steatosis during AFL and NALF. In the future, we plan to extend our observations to C57Bl/6 C5 deficient and A/J C5 sufficient mice. Financial support: FAPESP (09/05979-0). doi:10.1016/j.molimm.2010.05.226 49 Greater C5a generation in the BUB/BnJ mouse: Designing better mouse models to study the role of complement in degenerative diseases Tracy A. Cole, Karntipa Pisalyaput, Marie E. Benoit, Naseem Rowther, Andrea J. Tenner Dept Molecular Biology and Biochemistry and Neurobiology and Behavior, University of California, Irvine Mice have low levels of hemolytic activity in vitro as compared to human or rat serum, which results in uncertainty in the use of murine models to study of the role of complement in degenera- tive diseases such as Alzheimer’s disease and spinal cord injury. It is well established in the literature that male BUB/BnJ mice have greater complement hemolytic activity than male C57Bl6 mice. Therefore, we looked for differences in complement compo- nents between these mouse strains, which had not previously been investigated, to determine if the BUB mice would provide a more effective model to study the role of complement in neurodegener- ative diseases. When performing hemolytic activity experiments, it was found that while a percentage of lysis was due to antibody- and C1q-independent mechanisms in male BUB serum (which was not observed using male C57Bl6 serum), this did not account for the substantial difference in hemolytic activity seen between these two strains. Interestingly, while reactivity with a polyclonal anti- C4 antibody was seen in both C57Bl6 and BUB serum, a monoclonal antibody to mouse C4 showed reactivity only in C57Bl6 serum, con- sistent with a potential difference in C5 convertase activity. Similar protein levels of C5 and C6 were present in BUB and C57Bl6 mice, but C5a generation resulting from classical pathway activation was found to be significantly greater in male BUB mice in comparison to male C57Bl6 mice. Together, these data indicate that enhanced complement activity in BUB mice may be due to differences in C4, leading to differential cleavage of C5. Since inflammation con- tributes to neurodegenerative diseases, the generation of levels of C5a (generally proinflammatory) that more closely mimic that seen in humans may provide improved tools for characterizing the role of complement in disease as well as designing and testing thera- peutic strategies. Supported by NIH: NIA T32 AG00096 and P01 AG 00538. doi:10.1016/j.molimm.2010.05.227 5 Interactions between complement and neutrophil extracellular traps Jonatan Leffler, Myriam Martin, Anna M. Blom Department of Laboratory Medicine, The Wallenberg Laboratory Floor 4, UMAS Entrance 46, 205 02 Malmoe, Sweden Neutrophils are one of the first immune cells on site during infections. As an important player of the innate immune system they are very efficient in killing pathogens. Recently a novel killing mechanism was discovered related to generation of neutrophil extracellular traps (NETs). NETs are comprised mainly of DNA, his- tones and proteases that can capture and kill pathogens. NETs are subsequently degraded by DNases present in the blood. Deficien- cies of DNAse-I and C1q, an initiator of the complement system, are both associated with systemic lupus erythematosus (SLE). SLE is an autoimmune disease where antibodies against the main con- stituents of NETs are regularly found. In this study we investigated how complement interacts with the NETs and especially how DNA- binding proteins, C1q and the complement inhibitors C4b-binding