• Asian-Australasian Journal of Animal Sciences
• /
• v.28 no.9
• /
• pp.1354-1361
• /
• 2015

The complement system is a part of the natural immune regulation mechanism against invading pathogens. Complement activation from three different pathways (classical, lectin, and alternative) leads to the formation of C5-convertase, an enzyme for cleavage of C5 into C5a and C5b, followed by C6, C7, C8, and C9 in membrane attack complex. The C9 is the last complement component of the terminal lytic pathway, which plays an important role in lysis of the target cells depending on its self-polymerization to form transmembrane channels. To address the association of C9 with traits related to disease resistance, the complete porcine C9 cDNA was comparatively sequenced to detect single nucleotide polymorphisms (SNPs) in pigs of the breeds Hampshire (HS), Duroc (DU), Berlin miniature pig (BMP), German Landrace (LR), Pietrain (PIE), and Muong Khuong (Vietnamese potbelly pig). Genotyping was performed in 417 $F_2$ animals of a resource population (DUMI: $DU{\times}BMP$) that were vaccinated with Mycoplasma hyopneumoniae, Aujeszky diseases virus and porcine respiratory and reproductive syndrome virus at 6, 14 and 16 weeks of age, respectively. Two SNPs were detected within the third exon. One of them has an amino acid substitution. The European porcine breeds (LR and PIE) show higher allele frequency of these SNPs than Vietnamese porcine breed (MK). Association of the substitution SNP with hemolytic complement activity indicated statistically significant differences between genotypes in the classical pathway but not in the alternative pathway. The interactions between eight time points of measurement of complement activity before and after vaccinations and genotypes were significantly different. The difference in hemolytic complement activity in the both pathways depends on genotype, kind of vaccine, age and the interaction to the other complement components. These results promote the porcine C9 (pC9) as a candidate gene to improve general animal health in the future.

• Macromolecular Research
• /
• v.12 no.1
• /
• pp.46-52
• /
• 2004

In a continuation of our previous studies on blood compatibility profiles of anion-substituted poly(vinyl alcohol) (PVA) membranes, in which hydroxyl groups have been replaced with carboxymethyl (C-PVA) and sulfonyl groups (S-PVA), we have studied the activation of complement components and the changes in white cell and platelet count in vitro and compared them with those of unmodified PVA, Cuprophane, and low-density polyethylene. Complement activation of fluid phase components, C3a, Bb, iC3b, and SC5b-9, and of bound phases, C3c, C3d, and SC5b-9, were assessed by enzyme-linked immunosorbent assay (ELISA) and immunoblot, respectively. The changes in the number of white cells and platelets following complement activation were counted using a Coulter counter. C-PVA and S-PVA activated C3 to a lesser extent than did PVA, which we attribute to the diminished level of surface nucleophiles of the samples. In addition, C- and S-PVA exhibit increased inhibition of Bb production, resulting in a decrease in the extent of C5 activation. Consequently, because of the reduced activation of C3 and C5, C- and S-PVA samples cause marked decreases in the SC5b-9 levels in plasma. We also found that the negatively charged sulfonate and carboxylate groups of the samples cause a greater extent of adsorbtion of the positively charged anaphylatoxins, C3a and C5a, because of strong electrostatic attraction, which in turn provides an inhibition of chemotaxis and activation of leukocytes. The ability to inhibit complement production, together with the binding ability of anaphylatoxins of the C- and S-PVA samples, leads to a prominent decrease in lysis of leukocytes as well as activation of platelets.

• Parasites, Hosts and Diseases
• /
• v.60 no.4
• /
• pp.255-259
• /
• 2022

Heliminthic paramyosin is a multifunctional protein that not only acts as a structural protein in muscle layers but as an immune-modulatory molecule interacting with the host immune system. Previously, we found that paramyosin from Clonorchis sinensis (CsPmy) is bound to human complement C9 protein (C9). To analyze the C9 binding region on CsPmy, overlapping recombinant fragments of CsPmy were produced and their binding activity to human C9 was investigated. The fragmental expression of CsPmy and C9 binding assays revealed that the C9 binding region was located at the C-terminus of CsPmy. Further analysis of the C-terminus of CsPmy to narrow the C9 binding region on CsPmy indicated that the region flanking ⁷³¹Leu-⁷⁸⁰Leu was a potent C9 binding region. The CsPmy fragments corresponding to the region effectively inhibited human C9 polymerization. These results provide a precise molecular basis for CsPmy as a potent immunomodulator to evade host immune defenses by inhibiting complement attack.

• Clinical and Experimental Pediatrics
• /
• v.48 no.1
• /
• pp.101-103
• /
• 2005

Meningococcal disease is not rarely associated with abnormalities of the complement system. We experienced a case of C9 deficiency with meningococcal meningitis from a 12-year-old girl. Identification of complement deficiency has implications for management, including family studies, prophylaxis, vaccination, and altered threshold for infection screening and treatment.

• Childhood Kidney Diseases
• /
• v.10 no.1
• /
• pp.45-51
• /
• 2006

Hypocomplementemia is found in all types of membranoproliferative glomerulonephritis (MPGN) but not in all patients. Hypocomplementemia can be ascribed to at least two circulating complement reactive modalities. The activation of the classical pathway produced by circulating immune complexes and the presence in the blood of anticomplement autoantibodies, called 'nephritic factor'(NF). The activation of the classical pathway by circulating immune complexes is probably the major mechanism responsible for hypocomplementemia in idiopathic MPGN type I. Nephritic factors have been shown to be responsible for the hypocomplementemia in both MPGN type II and III. NFa is probably the major mechanism responsible for the hypocomplementemia of idiopathic MPGN type II. NFt appears to be solely responsible for the hypocomplementemia in MPGN type III. Judging from the complement profile, NFt also may be present in some patients with MPGN type I. Although infection by meningococcus has been associated with deficiency of any of the plasmatic proteins of complement, it more commonly involves deficiency of the terminal components of the complement pathway(C5-C9). We experienced a patient who had MPGN and meningococcal meningitis. We examined the complement level and significantly lower levels of C3, C5 were found persistently. C7 was low at first and it returned to normal range after 2 months. C9 was normal at first, and was low after 2 months. This is the first reported case in which MPGN with meningococcal meningitis occurred.

• Clinical and Experimental Pediatrics
• /
• v.52 no.6
• /
• pp.721-724
• /
• 2009

Meningococcal infections can be associated with abnormalities of the complement system, which contains 5 terminal complement proteins. Furthermore, deficiencies in 1 of these 5, complement component 7 (C7), leads to the loss of complement lytic function, and affected patients show increased susceptibility to recurrent meningococcal meningitis and systemic Neisseria gonorrhoeae infection. In September 2003, an 11-year-old female patient presented at our outpatient department with high fever, lower leg pain, headache, and petechiaes. She rapidly progressed to coma but later achieved full recovery due to prompt treatment. Her final diagnosis was meningococcal sepsis and arthritis. Her elder brother also had a similar bacterial meningoencephalitis history, which encouraged us to perform analyses for complement component and gene mutations. Resultantly, both the brother and sister were found to have the same mutation in the C7 gene. Subsequently, vaccinations of the meningococcal vaccine meningococcal vaccine ($Menomune^{(R)}$) were administered. However, in September 2006, the brother expired due to acute micrococcus meningoencephalitis. At present, the 16-year-old female patient is healthy. Here, we report a Korean family with a hereditary C7 deficiency with susceptibility to meningococcal infections due to C7 gene mutation.

• IMMUNE NETWORK
• /
• v.24 no.2
• /
• pp.17.1-17.16
• /
• 2024

We have reported that anterior cruciate ligament (ACL) injury leads to the differential dysregulation of the complement system in the synovium as compared to meniscus tear (MT) and proposed this as a mechanism for a greater post-injury prevalence of post traumatic osteoarthritis (PTOA). To explore additional roles of complement proteins and regulators, we determined the presence of decay-accelerating factor (DAF), C5b, and membrane attack complexes (MACs, C5b-9) in discarded surgical synovial tissue (DSST) collected during arthroscopic ACL reconstructive surgery, MT-related meniscectomy, osteoarthritis (OA)-related knee replacement surgery and normal controls. Multiplexed immunohistochemistry was used to detect and quantify complement proteins. To explore the involvement of body mass index (BMI), after these 2 injuries, we examined correlations among DAF, C5b, MAC and BMI. Using these approaches, we found that synovial cells after ACL injury expressed a significantly lower level of DAF as compared to MT (p<0.049). In contrast, C5b staining synovial cells were significantly higher after ACL injury (p<0.0009) and in OA DSST (p<0.039) compared to MT. Interestingly, there were significantly positive correlations between DAF & C5b (r=0.75, p<0.018) and DAF & C5b (r=0.64 p<0.022) after ACL injury and MT, respectively. The data support that DAF, which should normally dampen C5b deposition due to its regulatory activities on C3/C5 convertases, does not appear to exhibit that function in inflamed synovia following either ACL injury or MT. Ineffective DAF regulation may be an additional mechanism by which relatively uncontrolled complement activation damages tissue in these injury states.

• Journal of Veterinary Science
• /
• v.22 no.3
• /
• pp.36.1-36.12
• /
• 2021

Background: Mouse hepatitis virus (MHV) A59 is a highly infectious pathogen and starts in the respiratory tract and progresses to systemic infection in laboratory mice. The complement system is an important part of the host immune response to viral infection. It is not clear the role of the classical complement pathway in MHV infection. Objectives: The purpose of this study was to determine the importance of the classical pathway in coronavirus pathogenesis by comparing C1qa KO mice and wild-type mice. Methods: We generated a C1qa KO mouse using CRISPR/Cas9 technology and compared the susceptibility to MHV A59 infection between C1qa KO and wild-type mice. Histopathological and immunohistochemical changes, viral loads, and chemokine expressions in both mice were measured. Results: MHV A59-infected C1qa KO mice showed severe histopathological changes, such as hepatocellular necrosis and interstitial pneumonia, compared to MHV A59-infected wild-type mice. Virus copy numbers in the olfactory bulb, liver, and lungs of C1qa KO mice were significantly higher than those of wild-type mice. The increase in viral copy numbers in C1qa KO mice was consistent with the histopathologic changes in organs. These results indicate that C1qa deficiency enhances susceptibility to MHV A59 systemic infection in mice. In addition, this enhanced susceptibility effect is associated with dramatic elevations in spleen IFN-γ, MIP-1 α, and MCP-1 in C1qa KO mice. Conclusions: These data suggest that C1qa deficiency enhances susceptibility to MHV A59 systemic infection, and activation of the classical complement pathway may be important for protecting the host against MHV A59 infection.

• Journal of Preventive Medicine and Public Health
• /
• v.18 no.1
• /
• pp.91-97
• /
• 1985

The capacity of tobacco infusions of Korean cigarettes to activate the complement pathway was investigated in vitro by hemolytic assay. Complement activity was studied using samples of normal rabbit serum incubated at $37^{\circ}C$ with tobacco infusions. In all mixtures containing tobacco infusion A, B, C, D, E, F, G, H and I at a concentration of 0.1 : 1, total hemolytic complement showed a progressive decrease of 55.92%, 48.62%, 42.89%, 49.12%, 42.26%, 52.26%, 71.96%, 60.90%, and 61.14% respectively, after 60min of incubation. This study suggests that all tobacco infusions of Korean cigarettes are activators of complement.

• Archives of Pharmacal Research
• /
• v.26 no.6
• /
• pp.463-465
• /
• 2003

Four protostane-type triterpenes, alisol B 23-acetate (1a), alisol C 23-acetate (2a), alisol B(3a), and alisol A 24-acetate (4a), were isolated from the rhizome of Alismatis plantago-aquatica L. var. orientale Samuelson (Alismataceae) and eleven protostane derivatives (compounds 1-11) were obtained by selective modification from alisol B 23-acetate (1a). These compounds were investigated for their anti-complement activity against the classical pathway of the complement system. Alisol B (3a) and alisol A 24-acetate (4a) exhibited anti-complement activity with $IC_{50} values of 150 and 130 \mu$ M. Among the synthetic derivatives, the tetrahydroxylated protostane triterpene (9) showed moderate inhibitory activity with $IC_{50} value of 97.1 \mu$ M. Introduction of an aldehyde group at C-23 (10; $IC_{50} value, 47.7 \mu$ M) showed the most potent inhibitory effect on the complement system in vitro.