Preliminary genomic survey and sequence analysis of the complement system in non-eutherian mammals

2016 ◽  
Vol 38 (1) ◽  
pp. 80 ◽  
Author(s):  
Oselyne T. W. Ong ◽  
Lauren J. Young ◽  
Julie M. Old
Keyword(s):  
Complement System ◽  
Membrane Attack Complex ◽  
Tammar Wallaby ◽  
Monodelphis Domestica ◽  
Tasmanian Devil ◽  
Complement Components ◽  
Phascolarctos Cinereus ◽  
Ornithorhynchus Anatinus ◽  
Platypus Genome ◽  
The Complement System

The complement system is a major mediator of the vertebrate immune system, which functions in both innate and specific immune responses. It comprises more than 30 proteins working to remove foreign cells by way of anaphylatoxins, opsonins or the membrane attack complex. Over the last few years, whole genome sequences of non-eutherian mammals (marsupials and a monotreme), the gray short-tailed opossum (Monodelphis domestica), tammar wallaby (Macropus eugenii), Tasmanian devil (Sarcophilus harrisii), koala (Phascolarctos cinereus) and platypus (Ornithorhynchus anatinus), have become publicly available. Using these sequences, we have identified an array of complement components in non-eutherians using online search tools and algorithms. Of 57 complement and complement-related genes investigated, we identified 46 in the gray short-tailed opossum genome, 27 in the tammar wallaby genome, 44 in the Tasmanian devil genome, 47 in the koala genome and 40 in the platypus genome. The results of this study confirm the presence of key complement components in the immune repertoire of non-eutherian mammals and provide a platform for future studies on immune protection in young marsupials.

scholarly journals Systems Biology Modeling of the Complement System Under Immune Susceptible Pathogens

2021 ◽  
Vol 9 ◽  
Author(s):  
Nehemiah T. Zewde ◽  
Rohaine V. Hsu ◽  
Dimitrios Morikis ◽  
Giulia Palermo
Keyword(s):  
Complement System ◽  
Membrane Attack Complex ◽  
Factor H ◽  
Immunoglobulin M ◽  
The Body ◽  
Complement Components ◽  
Invasive Pathogens ◽  
Time Profiles ◽  
Related Proteins ◽  
The Complement System

The complement system is assembled from a network of proteins that function to bring about the first line of defense of the body against invading pathogens. However, complement deficiencies or invasive pathogens can hijack complement to subsequently increase susceptibility of the body to infections. Moreover, invasive pathogens are increasingly becoming resistant to the currently available therapies. Hence, it is important to gain insights into the highly dynamic interaction between complement and invading microbes in the frontlines of immunity. Here, we developed a mathematical model of the complement system composed of 670 ordinary differential equations with 328 kinetic parameters, which describes all three complement pathways (alternative, classical, and lectin) and includes description of mannose-binding lectin, collectins, ficolins, factor H-related proteins, immunoglobulin M, and pentraxins. Additionally, we incorporate two pathogens: (type 1) complement susceptible pathogen and (type 2) Neisseria meningitidis located in either nasopharynx or bloodstream. In both cases, we generate time profiles of the pathogen surface occupied by complement components and the membrane attack complex (MAC). Our model shows both pathogen types in bloodstream are saturated by complement proteins, whereas MACs occupy <<1.0% of the pathogen surface. Conversely, the MAC production in nasopharynx occupies about 1.5–10% of the total N. meningitidis surface, thus making nasal MAC levels at least about eight orders of magnitude higher. Altogether, we predict complement-imbalance, favoring overactivation, is associated with nasopharynx homeostasis. Conversely, orientating toward complement-balance may cause disruption to the nasopharynx homeostasis. Thus, for sporadic meningococcal disease, our model predicts rising nasal levels of complement regulators as early infection biomarkers.

scholarly journals Complement Proteins as Soluble Pattern Recognition Receptors for Pathogenic Viruses

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 824
Author(s):  
Valarmathy Murugaiah ◽  
Praveen M. Varghese ◽  
Nazar Beirag ◽  
Syreeta De Cordova ◽  
Robert B. Sim ◽  
...  
Keyword(s):  
Complement System ◽  
Membrane Attack Complex ◽  
Factor H ◽  
Complement Components ◽  
Diverse Range ◽  
Effector Functions ◽  
Pathogenic Viruses ◽  
Viral Survival ◽  
Chemotactic Factors ◽  
The Complement System

The complement system represents a crucial part of innate immunity. It contains a diverse range of soluble activators, membrane-bound receptors, and regulators. Its principal function is to eliminate pathogens via activation of three distinct pathways: classical, alternative, and lectin. In the case of viruses, the complement activation results in effector functions such as virion opsonisation by complement components, phagocytosis induction, virolysis by the membrane attack complex, and promotion of immune responses through anaphylatoxins and chemotactic factors. Recent studies have shown that the addition of individual complement components can neutralise viruses without requiring the activation of the complement cascade. While the complement-mediated effector functions can neutralise a diverse range of viruses, numerous viruses have evolved mechanisms to subvert complement recognition/activation by encoding several proteins that inhibit the complement system, contributing to viral survival and pathogenesis. This review focuses on these complement-dependent and -independent interactions of complement components (especially C1q, C4b-binding protein, properdin, factor H, Mannose-binding lectin, and Ficolins) with several viruses and their consequences.

Complement Components, C3 and C4, and the Metabolic Syndrome

2018 ◽  
Vol 15 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Melanie Copenhaver ◽  
Chack-Yung Yu ◽  
Robert P. Hoffman
Keyword(s):  
Metabolic Syndrome ◽  
Significant Role ◽  
Complement System ◽  
Gene Copy ◽  
Future Research ◽  
Obese Adults ◽  
Complement Components ◽  
Cardiometabolic Diseases ◽  
The Metabolic Syndrome ◽  
The Complement System

Introduction: Increased systemic inflammation plays a significant role in the development of adult cardiometabolic diseases such as insulin resistance, dyslipidemia, atherosclerosis, and hypertension. The complement system is a part of the innate immune system and plays a key role in the regulation of inflammation. Of particular importance is the activation of complement components C3 and C4. C3 is produced primarily by the liver but is also produced in adipocytes, macrophages and endothelial cells, all of which are present in adipose tissues. Dietary fat and chylomicrons stimulate C3 production. Adipocytes in addition to producing C3 also have receptors for activated C3 and other complement components and thus also respond to as well as produce a target for complement. C3adesArg, also known as acylation stimulation factor, increases adipocyte triglyceride synthesis and release. These physiological effects play a significant role in the development of metabolic syndrome. Epidemiologically, obese adults and non-obese adults with cardiometabolic disease who are not obese have been shown to have increased complement levels. C4 levels also correlate with body mass index. Genetically, specific C3 polymorphisms have been shown to predict future cardiovascular events and. D decreased C4 long gene copy number is associated with increased longevity. Conclusion: Future research is clearly needed to clarify the role of complement in the development of cardiovascular disease and mechanisms for its action. The complement system may provide a new area for intervention in the prevention of cardiometabolic diseases.

scholarly journals Development of a Novel Cytomedical Treatment that can Protect Entrapped Cells from Host Humoral Immunity

2002 ◽  
Vol 11 (8) ◽  
pp. 787-797 ◽  
Author(s):  
Ryo Suzuki ◽  
Yasuo Yoshioka ◽  
Etsuko Kitano ◽  
Tatsunobu Yoshioka ◽  
Hiroaki Oka ◽  
...  
Keyword(s):  
Humoral Immunity ◽  
Complement System ◽  
Alternative Pathway ◽  
Classical Pathway ◽  
Dependent Manner ◽  
Complement Components ◽  
Alternative Pathways ◽  
Low Cytotoxicity ◽  
The Complement System

Cell therapy is expected to relieve the shortage of donors needed for organ transplantation. When patients are treated with allogeneic or xenogeneic cells, it is necessary to develop a means by which to isolate administered cells from an immune attack by the host. We have developed “cytomedicine, ” which consists of functional cells entrapped in semipermeable polymer, and previously reported that alginate-poly-l-lysine-alginate microcapsules and agarose microbeads could protect the entrapped cells from injury by cellular immunity. However, their ability to isolate from humoral immunity was insufficient. It is well known that the complement system plays an essential role in rejection of transplanted cells by host humoral immunity. Therefore, the goal of the present study was to develop a novel cytomedical device containing a polymer capable of inactivating complement. In the screening of various polymers, polyvinyl sulfate (PVS) exhibited high anticomplement activity and low cytotoxicity. Murine pancreatic β-cell line (MIN6 cell) entrapped in agarose microbeads containing PVS maintained viability and physiological insulin secretion, replying in response to glucose concentration, and resisted rabbit antisera in vitro. PVS inhibited hemolysis of sensitized sheep erythrocytes (EAs) and rabbit erythrocytes by the complement system. This result suggests that PVS inhibits both the classical and alternative complement pathways of the complement system. Next, the manner in which PVS exerts its effects on complement components was examined. PVS was found to inhibit generation of C4a and Ba generation in activation of the classical and alternative pathways, respectively. Moreover, when the EAC1 cells, which were carrying C1 on the EAs, treated with PVS were exposed to C1-deficient serum, hemolysis decreased in a PVS dose-dependent manner. These results suggest that PVS inhibits C1 in the classical pathway and C3 convertase formation in the alternative pathway. Therefore, PVS may be a useful polymer for developing an anticomplement device for cytomedical therapy.

The complement system of the marsupial Monodelphis domestica

1998 ◽  
Vol 22 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Thomas L. Koppenheffer ◽  
Kay D. Spong ◽  
Heather M. Falvo
Keyword(s):  
Complement System ◽  
Monodelphis Domestica ◽  
The Complement System

Dynamic Expression of the Membrane Attack Complex (MAC) of the Complement System in Failing Human Myocardium

2006 ◽  
Vol 97 (11) ◽  
pp. 1626-1629 ◽  
Author(s):  
Guilherme H.M. Oliveira ◽  
Corinne N. Brann ◽  
Katy Becker ◽  
Vinay Thohan ◽  
Michael M. Koerner ◽  
...  
Keyword(s):  
Complement System ◽  
Membrane Attack Complex ◽  
Human Myocardium ◽  
Dynamic Expression ◽  
The Complement System

scholarly journals Immunity against the Obligate Intracellular Bacterial PathogenRickettsia australisRequires a Functional Complement System

2018 ◽  
Vol 86 (6) ◽  
Author(s):  
Sean P. Riley ◽  
Abigail I. Fish ◽  
Fabio Del Piero ◽  
Juan J. Martinez
Keyword(s):  
Complement System ◽  
Membrane Attack Complex ◽  
Immune Functions ◽  
Complement Protein ◽  
Membrane Pore ◽  
Content Type ◽  
Genetic Ablation ◽  
Obligate Intracellular ◽  
Susceptibility To Infection ◽  
The Complement System

ABSTRACTThe complement system has a well-defined role in deterring blood-borne infections. However, complement is not entirely efficacious, as several bacterial pathogens, including some obligate intracellular pathogens, have evolved mechanisms for resistance. It is presumed that obligate intracellular bacteria evade complement attack by residing within a host cell; however, recent studies have challenged this presumption. Here, we demonstrate that the complement system is activated during infection with the obligate intracellular bacteriumRickettsia australisand that genetic ablation of complement increases susceptibility to infection. Interaction ofRickettsia australiswith serum-borne complement leads to activation of the complement cascade, producing three effector mechanisms that could negatively influenceR. australis.The C9-dependent membrane attack complex can lead to deposition of a bacteriolytic membrane pore on the bacteria, but this system does not contribute to control of rickettsial infection. Similarly, complement receptor (CR1/2)-dependent opsonophagocytosis may lead to engulfment and killing of the bacteria, but this system is also dispensable for immunity. Nevertheless, intact complement is essential for naturally acquired and antibody-mediated immunity toRickettsiainfection. Comparison of infection in mice lacking the central complement protein C3 with infection in their wild-type counterparts demonstrated decreases in gamma interferon (IFN-γ) production, IgG secretion, and spleen hyperplasia in animals lacking complement. The correlation between loss of secondary immune functions and loss of complement indicates that the proinflammatory signaling components of the complement system, and not membrane attack complex or opsonophagocytosis, contribute to the immune response to this pathogen.

Introduction to the complement system

1984 ◽  
Vol 306 (1129) ◽  
pp. 279-281 ◽  
Keyword(s):  
Humoral Immunity ◽  
Complement System ◽  
Bacterial Infections ◽  
Cross Linking ◽  
Complement Components ◽  
The Third ◽  
Effector Mechanism ◽  
The Complement System

Complement is the essential effector mechanism in humoral immunity to infection. Combination of antibody with antigen causes cross-linking, leading to precipitation of soluble antigens and agglutination of particular antigens, but no more. Unless complement is also present, agglutinated microorganisms can, in appropriate media in vitro grow out and form as lethal a culture as if not reacted with antibody. That this is also true in vivo is apparent from experience with patients with inherited deficiencies in complement components. The pattern is complex because of the presence of two pathways of activation, but in the rare cases of deficiency of the third component, C3, which is central to both pathways, the individuals are susceptible to repeated bacterial infections similar to aggammaglobulinaemics who are unable to synthesize antibodies. Both antibodies and complement are essential for effective humoral immunity.

Solution structures of complement components by X-ray and neutron scattering and analytical ultracentrifugation

2002 ◽  
Vol 30 (6) ◽  
pp. 996-1001 ◽  
Author(s):  
S. J. Perkins ◽  
H. E. Gilbert ◽  
M. Aslam ◽  
J. Hannan ◽  
V. M. Holers ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Complement System ◽  
Analytical Ultracentrifugation ◽  
Factor H ◽  
Protein Domain ◽  
Complement Receptor ◽  
Complement Components ◽  
X Ray ◽  
Solution Studies ◽  
The Complement System

The short consensus/complement repeat (SCR) domain (also known as the complement control protein domain) is the most abundant domain type in the complement system. Crystal and NMR structures for proteins that contain single and multiple SCR domains have now been published. These contain inter-SCR linkers of between three and eight residues, and the structures show much variability in inter-SCR orientations. X-ray and neutron scattering, combined with analytical ultracentrifugation and constrained modelling based on known subunit structures will yield a medium-resolution structure for the protein of interest. The fewer parameters that are associated with the structure of interest, the more defined the structure of interest becomes. These solution studies have been applied to several SCR-containing proteins in the complement system, most notably Factor H with 20 SCR domains, a complement receptor type 2 fragment with two SCR domains, and rat complement receptor-related protein (Crry) which contains five SCR domains. The results show great conformational variability in the inter-SCR orientation, and these will be reviewed. Even though the rotational orientation cannot be modelled, it is nonetheless possible to measure the degree of extension of the multi-SCR proteins and, from this, to obtain functionally useful results.

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