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PubMed2003

Association of the porcine C3 gene with haemolytic complement activity in the pig.

The complement component C3 plays an essential role in the activated complement system, which is involved in phagocytosis, inflammation and immunoregulation to destroy infectious microorganisms. The C3 molecule has more implications in the general defence mechanisms. In this study, the porcine C3 cDNA sequences including 5'- and 3'- flanking regions were determined and the polymorphisms in this gene were identified to carry out an association analysis between C3 and complement activity traits. Porcine C3 gene has high homology with human C3. Five single nucleotide polymorphisms (SNPs) and one microsatellite were detected in the porcine C3 gene. Haemolytic complement activity of alternative and classical pathways (ACH, CCP) was measured in 416 F2 animals of a crossbred of Duroc x Berlin Miniature Pig, which were immunized with Mycoplasma, Aujeszky and PRRS vaccines. C3 markers were found to be significantly associated (P <0.05) with both ACP and CCP. Animals with the more frequent haplotype present in Duroc and other commercial breeds exhibit higher ACP and CCP levels than the animals with haplotype specific to some Berlin Miniature Pigs. The association of C3 with complement activity reinforces the importance of C3 as a candidate gene for natural resistance to microorganisms.

Animals↗
PubMed1992

Anti-leprosy drugs inhibit the complement-mediated solubilization of pre-formed immune complexes in vitro.

Incubation of pre-formed immune complexes (IC) (125I-HSA--anti-HSA) with normal human serum resulted in solubilization of IC. When various anti-leprosy drugs were added to human sera, solubilization of IC was fairly explicit with clofazimine, whereas this effect was marginal with dapsone. Rifampicin hardly displayed this effect. Aspirin, chloroquine, and prednisolone, the drugs used in addition to multi-drug therapy to control reactions in leprosy, were in a position to inhibit the solubilization of 125I HSA--anti-HSA by normal serum only at a very high dose. From the current data of the inhibition of solubilization of pre-formed IC along with our earlier observations on the modulation of complement-mediated haemolysis by these drugs, it may be possible to postulate that clofazimine as well as chloroquine affect early complement components. This may in turn be responsible for preventing the deposition of C3 complement onto IC.

Antigen-Antibody Complex↗
PubMed2006

House dust mites and allergic manifestations among some children in Dammam, Saudi Arabia.

The house dust mites is (=HDM) still one of the many causes of allergy, particularly atopic dermatitis. In the houses of children who were suffering allergic manifestations as atopic dermatitis, respiratory allergy, bronchitis, skin rash and fever. Double manifestations with fever were reported in four children. In the present study, two types of mites were recovered, Dermatophagoides farinae and Ornithonyssus bacoti. The immunoglobulins (G., M., A. & E) as well as complements (C3 & C4) were measured in the patients and cross-matched controls. The complements did not show any significant difference among patients and controls. Elevation was detected in IgG and IgM, but not in IgA. However, high significant elevation was in IgE. The results were discussed on the light of regional work.

Adolescent↗
PubMed1989

[Serological and immunohistochemical studies in pregnant women with systemic lupus erythematosus].

The present report is a detailed, prospective analysis of 29 pregnancies in 19 patients with systemic lupus erythematosus (SLE). The clinical pregnant status was correlated with maternal serologic patterns. Poor obstetrical prognosis was associated with low or declining complement (C3 and C4) levels and rising antinuclear and anti-DNA antibody titers. Complement levels reflected clinical changes more accurately than either antinuclear factor. A smooth antepartum course and successful delivery occurred when complement values remained normal. Immunohistochemical studies showed granular or linear depositions of immunoglobulin and complement on syncytial trophoblast and stromal tissue in placenta with SLE. Slight deposits of IgG were observed on the stromal tissue in normal placenta. Immune complex deposition on the trophoblast correlated to both serologic evaluation and course of SLE pregnancy. Obstetrical prognosis can be evaluated by serial determinations of serologic status. These data suggest that declining levels of maternal complements in SLE may be partly due to immune complex deposition in the placenta, resulting in the increased placental dysfunction.

Antibodies, Antinuclear↗
PubMed1994

Characterization and immortalization of woodchuck hepatocytes isolated from normal and hepadnavirus-infected woodchucks (Marmota monax).

Primary woodchuck (Marmota monax) hepatocytes from normal woodchucks and woodchucks with chronic woodchuck hepatitis virus (WHV) infection were cultured in either a conventional serum-containing medium or a serum-free medium. The de novo synthesis of the plasma proteins albumin, transferrin, fibrinogen, and complement C3 were identical under both conditions. However, expression of the WHV and the synthesis of nitric oxide were diminished under serum-free conditions. Primary woodchuck hepatocytes cultured in conventional, serum-containing medium were immortalized utilizing the simian virus 40 T antigen oncogene. Immortalized hepatic cell lines retained differentiated functions of nitric oxide synthesis and expression of complement C3. The woodchuck hepatocyte culture model will supplement current experimental methods, allowing investigation of hepadnaviral pathogenesis, including hepatocarcinogenesis in vitro.

Albumins↗
PubMed2000

Ligand structure-dependent differences in activation of estrogen receptor alpha in human HepG2 liver and U2 osteogenic cancer cell lines.

Differences in ligand-activation of estrogen receptor alpha (ER(alpha)) were investigated in human HepG2 liver carcinoma and U2 osteogenic sarcoma cells transfected with wild-type ER (ER-wt) and variants expressing only activation function 1 (ERAF1) or AF2 (ER-AF2). The estrogen-responsive C3-luc construct containing the complement C3 gene promoter linked to a bacterial luciferase reporter gene was used to determine ligand-induced wild-type or variant ER activation. The quality pattern of ER-dependent responses was similar in both cell lines for a series of weakly estrogenic hydroxy and dihydroxyaromatic compounds including p-octylphenol, p-nonylphenol, 2',4',6'-trichloro-4-biphenylol, 2',3',4', 5'-tetrachloro-4-biphenylol, bisphenol A and 2, 2'-bis(p-hydroxyphenyl)-1,1,1-trichloroethane. However, some significant quantitative differences in these compounds were also observed. The weakly estrogenic pesticide, kepone, and the phytoestrogens, resveratrol (a trihydroxystilbene) and naringen (a flavanone), induced distinctly different patterns of responses; induction by these compounds was not observed in either cell line cotransfected with ER-wt or ER-AF2. In contrast, naringen activated ER-AF1 in HepG2 cells and resveratrol activated ER-AF1 in U2 cells. In HepG2 cells cotreated with E2 plus the estrogenic compounds, only BPA and resveratrol exhibited ER(alpha) antagonist activity. Structure-dependent differences in ER(alpha) activation and inhibition are consistent with the increasingly complex patterns of ER action in various tissues and indicate that the estrogenic activity of an individual compound can only be determined by using an extensive testing protocol.

Animals↗
PubMed1987

Bf and C3 polymorphisms in rheumatoid arthritis.

Properdin factor B (Bf) and complement C3 polymorphisms were studied in 225 unrelated rheumatoid arthritis (RA) patients from North-East England. Patients were subdivided on the presence or absence of significant titres of rheumatoid factor and antinuclear factor. No association with the C3 system was detected. For the Bf system, a significant excess of Bf SS and deficiency of Bf FS phenotypes was observed in seropositive RA patients lacking antinuclear antibodies. This finding suggests that auto-antibody-defined subgroups of RA may be genetically heterogeneous with respect to Bf and confirms the status of Bf SS phenotype as a marker for RA susceptibility and/or severity.

Antibodies, Antinuclear↗
PubMed1988

Acid protease activity of a major surface membrane glycoprotein (gp63) from Leishmania mexicana promastigotes.

A unique protease with activity optimal at pH 4.0 and trailing toward the alkaline pH spectrum was detected with intact glutaraldehyde-fixed promastigotes of Leishmania mexicana amazonensis, indicating surface localisation of the enzyme. That this surface protease may be a virulence factor is suggested by its apparent roles in multiple steps during leishmanial infections of macrophages. Indeed, its specific activity was 2-2.5 fold higher on virulent cells than on avirulent cells. Several lines of evidence indicate that this acid protease activity is expressed by the major surface glycoprotein (gp63) of L. m. amazonensis. Monoclonal antibody affinity purified gp63 degraded serum albumin, hemoglobin, complement C3, immunoglobulin G and purified rat liver lysosomal proteins in their native forms. The specific activity is about 20-fold higher at pH 4.0 than at pH 7.5 and is about four-fold higher at the body temperature of the mammalian host (37 degrees C) than at that of the insect host (27 degrees C). The protease activity is sodium dodecyl sulphate-sensitive. Among various protease inhibitors tested, only heavy metal ions (1 mM), 1,10-orthophenanthroline (1 mM) and bestatin (100 ng ml-1) significantly inhibited gp63 acid protease activity by up to 80%. N-linked oligosaccharides of gp63 appear to be important for the stability of this molecule, possibly by preventing its autodegradation. Purified gp63 effected limited proteolysis of human complement C3 molecules at the physiological serum pH of 7.5 in a manner, which supports the idea of its participation in complement-receptor mediated endocytosis of promastigotes by macrophages.

Animals↗
PubMed1989

Opsonic activity in serum from septic infants treated with intravenous immunoglobulin.

Thirteen infants with staphylococcal sepsis and reduced opsonic activity received infusions of acid treated immunoglobulin together with antibiotics. Opsonic activity (using Staphylococcus aureus (type 42D) as the test organism), haemolytic activity of complement, and concentrations of complement C3 and IgG were measured in serum prepared before and after three days of treatment with immunoglobulin at a dose of 250-300 mg/kg/day. There was increased ingestion of S aureus by normal human granulocytes in the presence of fresh serum prepared after infusion of immunoglobulin and significantly increased opsonic activity of heat inactivated serum after treatment with immunoglobulin. The haemolytic activity of complement and concentrations of complement C3 were not influenced, and serum concentrations of IgG increased as the result of receiving a total of 800-900 mg/kg immunoglobulin over a period of three days. This study shows that administration of acid treated IgG to septic infants leads to functionally increased opsonisation.

Complement C3↗
PubMed1998

Evaluation of seminal plasma parameters in patients with chronic prostatitis or leukocytospermia.

Though detailed cytological and microbiological diagnostic procedures are routinely carried out in male genital tract infection, the correct diagnosis and localization of inflammation or infection is often difficult. In this prospective study, the relevance of the seminal plasma markers PMN elastase, complement C3, CRP, fructose, PSP 94, PSA, and alpha-glucosidase was investigated in 13 patients with chronic prostatitis, 31 patients with significant leukocytospermia, and 58 patients with non-inflammatory diseases (controls). Statistically relevant results were obtained for PMN elastase when comparing chronic prostatitis with controls, leukocytospermia with controls (P < 0.001) and chronic prostatitis with leukocytospermia (P < 0.05); for complement C3 chronic prostatitis and leukocytospermia vs. controls (P < 0.05) and for fructose/ejaculate leukocytospermia vs. controls (P < 0.05). No statistically relevant differences were found for C-reactive protein, alpha-glucosidase, PSA and prostatic secretory protein (PSP 94). To delimit genital tract inflammation from non-inflammatory patients, cutpoint levels for PMN elastase of 230 ng ml-1 and for C3c of 0.01 g l-1 were suggested. PMN elastase was shown to possess the strongest discriminating power. The assessment of a cutpoint for fructose to indicate seminal vesicle dysfunction is not possible as the significance level is weak (P < 0.05).

Adolescent↗
PubMed2004

Amelioration of lupus manifestations by a peptide based on the complementarity determining region 1 of an autoantibody in severe combined immunodeficient (SCID) mice engrafted with peripheral blood lymphocytes of systemic lupus erythematosus (SLE) patients.

A peptide based on the complementarity determining region (CDR)1 of a human monoclonal anti-DNA autoantibody (hCDR1) was shown to either prevent or treat an already established murine lupus in systemic lupus erythematosus (SLE)-prone mice or in mice with induced experimental SLE. The present study was undertaken to determine the therapeutic potential of hCDR1 in a model of lupus in severe combined immunodeficient (SCID) mice engrafted with peripheral blood lymphocytes (PBL) of patients with SLE. To this end, PBL obtained from lupus patients were injected intraperitoneally into two equal groups of SCID mice that were treated either with the hCDR1 (50 micro g/mouse) once a week for 8 weeks, or with a control peptide. Mice were tested for human IgG levels, anti-dsDNA autoantibodies, anti-tetanus toxoid antibodies and proteinuria. At sacrifice, the kidneys of the successfully engrafted mice were assessed for human IgG and murine complement C3 deposits. Of the 58 mice transplanted with PBL of SLE patients, 38 (66%) were engrafted successfully. The mice that were treated with the control peptide developed human dsDNA-specific antibodies. Treatment with hCDR1 down-regulated the latter significantly. No significant effect of the treatment on the levels of anti-tetanus toxoid antibodies could be observed. Treatment with hCDR1 resulted in a significant amelioration of the clinical features manifested by proteinuria, human IgG complex deposits as well as deposits of murine complement C3. Thus, the hCDR1 peptide is a potential candidate for a novel specific treatment of SLE patients.

Adoptive Transfer↗
PubMed1979

Comparison of in vivo and in vitro capability of complement fixation by pemphigus antibodies.

Using complement immunofluorescence, the capability of complement fixation by bound antibodies in pemphigus lesional skin was compared with circulating intercellular antibodies of complement-fixing type in the same patient. Five lesional skin samples from 6 patients, containing bound IgG, gave positive binding of complement (C3) supplied from fresh guinea pig serum, while only one serum sample showed complement-fixing pemphigus antibodies in the circulation. These results support the view that complement-fixing pemphigus antibodies are rapidly localized to the skin and play a role on the production of acantholysis.

Antibodies↗
PubMed1997

Activation, binding, and processing of complement component 3 (C3) by Blastomyces dermatitidis.

Complement plays a key role in phagocyte recognition and killing of Blastomyces dermatitidis, but little is known about how complement components interact with the yeast. We report the characteristics of activation, binding, and processing of C3 by B. dermatitidis. In pooled normal human serum (NHS), deposition of C3 on the yeast was detectable within 2 min, whereas in NHS containing MgEGTA, deposition was delayed by 6 min, indicating that the yeast activates C3 by both classical and alternative pathways. When both pathways were operative, maximal binding of 4.5 x 10(6) C3 molecules/cell was achieved in less than 30 min. In the absence of the classical pathway, yeast cells bound 80% of the maximum C3, indicating that the yeast intrinsically activates the alternative pathway. Delayed deposition of C3 in NHS-MgEGTA was similar to that in NHS preabsorbed by the yeast or by immobilized protein A/G to remove serum immunoglobulin. Purified immunoglobulin restored C3 binding to NHS preabsorbed by the yeast, suggesting that antibody in nonimmune serum initiates the classical pathway. beta-Glucan absorption of NHS abolished the classical pathway, suggesting that cell wall beta-glucan is a target of initiating antibodies. Hydroxylamine treatment of NHS-opsonized yeast cells showed that 76% of C3 was bound to yeast cells by ester linkage, supporting a role for hydroxyl groups on cell wall polysaccharides. Hydroxylamine-cleaved fragments were chiefly C3b and iC3b; 70% of hydroxylamine-sensitive C3b was converted to iC3b within 1 min of opsonization, and the ratio was stable over 1 h. Our data predict that C3b and iC3b on opsonized yeast cells direct binding to CR1 and CR3 receptors on human phagocytes, which, in turn, may influence the fate of this host-pathogen interaction.

Blastomyces↗
PubMed1993

Hereditary deficiency of C3 in animals and humans.

Inherited deficiency of complement C3 has been described in guinea pigs, dogs and 20 humans. Homozygous deficiency of C3 is associated with recurrent pyogenic infections by encapsulated bacteria, especially H. influenzae, S. pneumoniae and N. meningitidis. In dogs and humans there is also an association with development of glomerulonephritis of the mesangiocapillary type. Some patients also develop transient erythematous rashes in association with pyogenic infections, with histology showing predominantly neutrophil infiltration and small vessel vasculitis. Studies of antibody responses, mainly in experimental animals have shown impaired primary and secondary responses to both thymus-dependent and -independent antigens at low immunizing doses, with a reduced switch from IgM to IgG production. The molecular basis of C3 deficiency has been established in two humans with C3 deficiency. In one it was due to a splice junction mutation and in another, to a partial gene deletion. These mutations are not compatible with the production of functional C3 in any tissue. Such patients with absolute C3 deficiency are a valid model for understanding the physiological role of C3 in vivo.

Animals↗
PubMed1993

Genetic markers for chronic bronchitis and peak expiratory flow in the Copenhagen Male Study.

The associations between four major blood groups, ABH secretor status, and complement C3, and chronic bronchitis and peak expiratory flow were examined in 3387 men, aged 55-74 years. Presence of chronic bronchitis was assessed using the British Medical Research Council (BMRC) questionnaire. Men with NS- in the MNS system had significantly less chronic bronchitis than others, i.e. 11.4% versus 16.0% (p < 0.0005). In heavy smokers, both men with NS- and NS+ had significantly less chronic bronchitis than others. Also, Rhesus positive men had less chronic bronchitis than Rhesus negative men, 28.0% versus 38.3% (p < 0.05). Absence of the complement C3 allele C3F was associated with a higher prevalence of chronic bronchitis. No association with chronic bronchitis was found for the AB0 system or the ABH secretor system. No convincing associations were found between genetic markers and mean peak flow. In conclusion, this study has suggested new genetic markers for respiratory disease indicating a partly genetic aetiology of chronic respiratory disease. The MNS, and to some extent the Rhesus blood groups, were associated with chronic bronchitis in middle-aged men. However, this study demonstrates once again that no single blood type can act as a risk indicator of chronic respiratory disease.

ABO Blood-Group System↗
PubMed1999

A possible role for activated complement component 3 in phagocytic activity exhibited by the mouse trophoblast.

PROBLEM: To determine whether any blood plasma factor may play a regulatory role in trophoblast phagocytosis in rodent early pregnancy. METHOD OF STUDY: The effects of alloplasma on the phagocytosis of cultured mouse trophoblast cells (TCs) were evaluated using erythrocytes as target cells, in the presence of 10% fresh, normal plasma; 10% heat-inactivated plasma; 10% component 3 (C3)-depleted plasma; or medium alone. The possible activation of C3 complement, the phagocytosis of zymosan bound or unbound to C3b, and immunoreactivity to C3b receptor were also estimated. Phagocytic activity was expressed as the percentage of phagocytic TCs, and as the number of phagosomes/TCs. RESULTS: The use of complement sufficient plasma significantly enhanced the phagocytosis of the TCs while the use of heat-inactivated plasma eliminated the erythrophagocytosis. Very low levels of phagocytic activity were seen when the plasma was C3-complement deficient. Phagocytosis of C3b-bound zymosan was remarkable in comparison to zymosan alone, and immunoreactivity to C3b-receptors was seen on the TCs. CONCLUSION: These results indicate the participation of thermosensitive molecules mediating the phagocytosis of TCs and suggest, as in macrophages, a role for C3-C3b in this process.

Animals↗
PubMed1990

Role of circulating immune complexes in the immunopathogenesis of silicosis.

The sera of 19 silica-dust-exposed subjects and of an equal number of age-, sex- and socioeconomic-strata-matched controls were analysed for antinuclear factor, rheumatoid factor, C-reactive protein, immunoglobulins G, M, A, and complement C3 and C4. Circulating immune complexes were also precipitated in all subjects and their immunoglobulin and complement C3 and C4 were estimated. Silica-exposed subjects were divided into two groups depending upon the radiological findings and it is suggested that IgA plays an important role in the immunopathogenesis of the disease and that lung changes could be due to the immune-complex-mediated mechanisms utilizing an alternative complement pathway.

Adolescent↗