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At least 145 records · Page 8Linked to original sources
PubMed1989

C7 polymorphism in Japanese: new allele C7*8.

The polymorphism of C7 was investigated in neuraminidase-treated sera from 513 unrelated Japanese individuals using isoelectric focusing followed by an electroimmunoblotting technique. Besides the common phenotypes 5 rare variants including 2 types of new variants were detected. The family analysis suggested the hereditary occurrence of a new allele C7*8. The allele frequencies were: C7*1 = 0.8314, C7*2 = 0.0926, C7*3 = 0.0380, C7*4 = 0.0331, C7*6 = 0.0010, and C7*8 = 0.0039.

Alleles↗
PubMed1992

Combined total deficiency of C7 and C4B with systemic lupus erythematosus (SLE).

The first inherited combined total deficiency of C7 and C4B complement components associated with SLE is described in a young female. Functional C7 assays showed a homozygous C7 deficiency in the propositus and her sister, and an heterozygous one in their parents. C4 molecular analyses showed that both the propositus and her mother had two HLA haplotypes carrying only C4A-specific DNA sequences and a normal C4 gene number. Thus, only C4A proteins could be expressed, with resultant normal C4 serum levels. The coexistence of a combined complete C7 and C4B deficiency may therefore abrogate essential functions of the complement cascade presumably related to immune complex handling and solubilization despite an excess of circulating C4A. These findings challenge the putative pathophysiological roles of C4A and C4B and stress the need to perform both functional assays and C4 allotyping in patients with autoimmune pathology and low haemolytic activity without low serum levels of a classical pathway complement component.

Adult↗
PubMed1990

C7*9, a new frequent C7 allele detected by an allotype-specific monoclonal antibody.

Two sandwich ELISA for the quantitation of C7 in human plasma--one based on a monoclonal (MAb), the other performed with a polyclonal anti-C7 IgG--were established. Results from ELISA as well as from isoelectric focussing and immunoblotting with both antibodies revealed that the MAb is directed to an allotypic epitope on C7. About 6.7% of the plasma samples did not react with this MAb. Since these findings cannot be explained by the known alleles, the existence of a new C7 allele, C7*9, was suggested, whose product C7-9 is not detected by the MAb. A gene frequency of 0.21 C7*9 was assumed. When using conventional techniques C7*9 is included in the frequency of C7*1.

Alleles↗
PubMed1984

Detection of terminal complement components in experimental immune glomerular injury.

Complement mediates glomerulonephritis by inflammatory cell-dependent and non-inflammatory cell-independent effects on glomerular permeability. The latter may involve terminal components of the complement system. We examined several models of immunologic renal injury in the rat by immunofluorescence (IF) for terminal complement components C5, C6, C7, and C8 in glomeruli using antisera to human C5-8, which cross-react with the analogous rat complement components. Rats with the heterologous and autologous phases of passive Heymann nephritis (PHN) had proteinuria and 1 to 2+ capillary wall deposits of heterologous or rat IgG, rat C3, and C5-8. Complement depletion with cobra venom factor (CVF) significantly decreased proteinuria in both models and prevented deposition of all complement components. Rats with active Heymann nephritis had similar deposits of rat IgG and C5-8. Rats with anti-GBM nephritis and aminonucleoside nephrosis had severe proteinuria which was not affected by CVF treatment and deposits of C5-8 were absent. The presence of terminal complement components in immune deposits in experimental glomerular disease correlates with a functional role for complement in mediating glomerular injury. These data support the hypothesis that the terminal complement pathway may be a major mediator of some types of immune glomerular injury.

Animals↗
PubMed1987

Combined familial C7 and C4B deficiency in an adult with meningococcal disease.

A case of meningococcal septicaemia is reported in an adult with a deficiency of the seventh component of complement combined with a deficiency of the B locus product of C4. A family study demonstrated that the two deficiencies were not linked. This is the first time that the individual alleles of C4 were determined in a patient with a deficiency of one component of the terminal pathway. It is possible that the heterogeneous clinical picture of a terminal pathway deficiency may, in part, be explained by the co-existence of other subtle complement defects.

Adult↗
PubMed1986

Inherited deficiency of the seventh component of complement associated with meningococcal meningitis: lack of serum bactericidal activity against Neisseria meningitidis in a girl with C7 deficiency and HLA studies of a C7-deficient Japanese family.

An 8-year-old girl with meningococcal meningitis lacked serum complement activity. The seventh component of complement (C7) could not be detected in her serum by either functional or immunochemical analysis. The levels of the other components were within the normal range. Her serum complement activity was restored by the addition of purified C7. Her fresh serum showed a total absence of bactericidal activity against Neisseria meningitidis, group Y, but her serum bactericidal activity was restored by the addition of purified C7. The restoration of her serum bactericidal activity was completely inhibited in the presence of Mg2+ EGTA. These findings suggest that restoration of the bactericidal activity of her serum against N. meningitidis might be mediated by the specific antibody against N. meningitidis and the reconstituted complement system in her serum. Heterozygous deficiency of C7 was found in 10 of her family members. Genetic studies showed that the mode of inheritance might be an autosomal codominant trait. No genetic linkage between deficiency of C7 and the HLA system was found.

Blood Bactericidal Activity↗
PubMed1986

The pore-forming protein (perforin) of cytolytic T lymphocytes is immunologically related to the components of membrane attack complex of complement through cysteine-rich domains.

Structural, functional and immunological similarities between the ninth component of complement (C9) and the lymphocyte pore-forming protein (PFP, perforin) have recently been described (8-10). PFP is shown here to be immunologically related to all other components of the membrane attack complex (MAC) of human complement, namely, C5b-6, C7, C8, and C9. Polyclonal antibodies raised against purified human C5b-6, C7, C8, or C9 react with other components of the MAC and with mouse lymphocyte PFP. The antigenic epitopes shared by human complement proteins and mouse lymphocyte PFP are limited to cysteine-rich domains. Only complement proteins that have been reduced and alkylated elicit the production of crossreactive antibodies when used as immunogens. The nonreduced forms of complement components or lymphocyte PFP neither react with these antibodies nor give rise to crossreactive antibodies. The homologous domains of complement proteins and lymphocyte PFP may play related functions in their attachment to lipid membranes and assembly of membrane lesions.

Animals↗
PubMed1991

[Purpura fulminans and C7 deficiency complicated by Pneumocystis carinii pneumonia].

A case of meningococcal purpura fulminans is reported in a 22-year-old woman who also suffered from a congenital deficiency in the seventh component of the complement system. This was her third episode of recurrent meningitis. In the course of her treatment in intensive care, the septic shock was cured, but she developed Pneumocystis carinii pneumonia. Histological investigations revealed abnormalities in her T-cell population, with a very low T-helper (CD4) to T-suppressor (CD8) ratio. Laboratory data showed that she did not have any antibodies to HIV.

Adult↗
PubMed1989

Molecular cloning and characterization of the novel, human complement-associated protein, SP-40,40: a link between the complement and reproductive systems.

The cDNA sequence encoding the human complement-associated protein, SP-40,40, is reported. The two chains of SP-40,40 are coded in a single open reading frame on the same mRNA molecule, indicating the existence of a biosynthetic precursor protein which matures post-synthetically by the proteolysis of at least one peptide bond. The precursor is preceded by a signal sequence for vectorial export and contains six N-linked glycosylation sites distributed equally between the two chains of the structure. The sequence of the SP-40,40 precursor bears a 77% identity to a rat sulphated glycoprotein-2 (SGP-2) which is the major secreted product of Sertoli cells. The presence of SP-40,40 within human seminal plasma at levels comparable to those in serum was demonstrated, indicating that SP-40,40 and SGP-2 are serum and seminal forms of the same protein. A sequence of 23 amino acids within the beta-chain of SP-40,40 exhibited significant homology to corresponding segments located within complement components C7, C8 and C9. The short cysteine-containing motif represented the only evidence of a possible vestigial relationship between SP-40,40 and other complement components. The precise role of SP-40,40 is not known in either blood or semen but the present findings document an intriguing link between the immune and the reproductive systems.

Amino Acid Sequence↗
PubMed1976

Purification of the sixth and seventh component of human complement without loss of hemolytic activity.

Procedures for the isolation of the human complement proteins C6 and C7 have been described. These procedures allow isolation of the two proteins without any loss of hemolytic activity. Apparent activity gains of 160% and 140% were observed for C6 and C7, respectively, when the activity of the isolated proteins was compared with their activity in serum. The recovery of C6 was 3.5 to 11% and that of C7 was 7 to 13% of the amount present in serum. C6 has a m.w.of 128,000 and an electrophoretic mobility at pH 8.6 of -2.6 times 10(-5) cm2 s-1 v-1. C7 has a m.w. of 121,000 and an identical electrophoretic mobility. With 3 times 10(7) assay cells, 63% hemolysis was achieved with 1 ng of C6 and 3.8 ng C7. On polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and after reduction with mercaptoethanol, C6 and C7 behaved as single polypeptide chain proteins.

Complement C6↗
PubMed1976

Separation of six bovine complement components and one inactivator (1, 2).

Six components (C1, C5, C6, C7, C8 and C9) of bovine complement and one inactivator (C3 in) could be separated from bovine serum. Bovine C1 was separated by precipitation at low molarity (0.03 M of relative salt concentration) other components by DEAE-cellulose chromatography using 0.005 M sodium phosphate buffer, pH 7.5, as a base for solvents having the relative salt concentration adjusted by addition of NaCl from 0.03 to 0.3 M. The separated bovine complement components could be tested using intermediates formed from sheep erythrocytes, rabbit hemolysin, guinea pig C1 and remaining human complement components. C2, C3 and C4 of bovine origin remained undetected either because of incompatibility with the intermediates used or interference of inhibitors or inactivators.

Animals↗
PubMed1988

Three Japanese families with members carrying C7 silent allele (C7*Q0). Possibility for an association between C7*Q0 and C6*B.

Three Japanese families with members carrying C7 silent allele(s) (C7*Q0) are presented. C6 types in the family members were also examined, and it was found that C7*Q0 was transmitted from a parent to offsprings as a haplotype, C7*Q0-C6*B. In another study of C6 types in sera from 3 volunteer blood donors with homozygous C7 deficiencies, the C6 phenotypes were found to be C6 B (homozygote). It seems remarkable that C7*Q0 can be associated with C6*B.

Alleles↗
PubMedDate not supplied

[C7 typing of blood stains using isoelectric focusing and immunoblotting].

By means of isoelectric focusing and immunoblotting C7 types were clearly demonstrated from bloodstains which had been stored at 37 degrees C for up to three weeks, at room temperature for up to six weeks and at 4 degrees C for over ten weeks. The C7 typing is practically useful in medicolegal individualization of unknown bloodstains.

Alleles↗