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PubMed1978

Testing of hemolytic complement components in domestic animals.

Total complement (C) and its components were assayed in the serum of 8 species of domestic animals, using commercially prepared cellular intermediates of sheep erythrocytes and functionally pure guinea pig and human components of the C system. Testing was done according to methods recommended by the producer for testing human C components. The late-acting components (C6 throug C9) and C1 were detected in carnivorous (dog and cat) and omnivorous (swine) animals. Undetectable or low titers of C4, C2, C3, and C5 were present in large herbivorous animals (cattle, horse, sheep, and goat), indicating major differences in comparison with human or guinea pig components of C. Porcine serum contained an inhibiting substance which interfered with testing C2 and later-acting components at serum dilutions up to 1:100. All components except C2 were detected in chicken serum. The binding or activation (or both) of C4, C2, C3, and C5 is more species specific than is the binding or activation (or both) of other components. Requirements for species specificity between antibody and C1 were not detected. Presence of C1 inactivator was detected in bovine, caprine, equine, and ovine sera. The CH50 (50% hemolysis) titers of C components tested in pooled serum samples from the 8 species of clinically healthy domestic animals are presented.

Animals↗
PubMed1978

The structural events associated with the attachment of complement components to cell membranes in reactive lysis.

Electron microscopic study of the events occurring at the cell membrane during reactive lysis by complement, showed that a foliaceous particle was formed at the C5b-7 stage, that enlarged to a particle with a variable number of arms at the C5b-8 stage. Up to this point, no typical complement lesions were found. At the C5b-9 stages, the particles were completely converted to typical complement lesions, i.e. hollow cylinders projecting from the cell membrane and partly penetrating it. C5b-9 complexes assembled in the fluid phase did not show the typical structure of the lesions, but were amorphous masses of fibres.

Complement C5↗
PubMed1976

Deviated lysis: Transfer of complement lytic activity to unsensitized cells II. Generation of the activity by inulin and by antigen antibody complexes.

Deviated lysis (d.l.) activity, i.e. lysis of unsensitized cells by lytic C activity, was generated via the classical pathway of Cactivation (ag ab complexes) and via the alternative pathway (inulin). The activity was observed on the surface of the activating particles and in the fluid phase. The activity was relatively stable at 32 degrees C. Its generation involved the C components C6 through C9 and possibly also C5.

Animals↗
PubMed1977

Deviated lysis: transfer of complement lytic activity to unsensitized cells. IV. Parital isolation of the activity.

Deviated lysis (d.l.) was previously characterized as the lysis of non-sensitized erythrocytes by activated complement (C) in the presence of EDTA (1, 2, 3). The lytic activity was present in serum fractions of a m.w. in the proximity of 220,000. All the C factors C5 through C9 were found in these fractions and they were all needed for lysis. It is proposed that in d.l. small aggregates of the C components C5 through C9 coexist in the reaction mixture without further interaction. Only when appropriate receptors such as present on target cells surfaces are available, the factors react in a sequential order eventually to result in lysis of the target cell.

Animals↗
PubMed1977

Complement system in human colostrum: presence of nine complement components and factors of alternative pathway in human colostrum.

Evidence has been obtained for the presence in human colostrum of all nine components of complement (C), C1 through C9, and factors of the alternative pathway. Samples of colostrums collected from five women at 1-4 days after normal parturition were assayed for the haemolytic activities of individual components. As compared with normal human sera, the activities of each component ranged from 0.03 to 7% of those in sera. The activities of C4, C7 and C9 were relatively high, while that of C1 was extremely low. In most of the cases, the activities of individual components gradually increased following delivery, when expressed as the activity per unit weight (g) of protein in the colostrum. When the colostrums were treated with cobra venom factor, most of the colostrums showed 10-20% reduction in the C3 activity. This finding indicates the presence of factors such as B and D which are involved in the activation of C through the alternative pathway. The role as a defense factor of the C system in human colostrum and milk is discussed in connection with the ability of secretory IgA to react with C.

Colostrum↗
PubMed1992

Enhanced expression of the complement-regulatory factor C8 binding protein (C8bp) on U937 cells after stimulation with IL-1 beta, endotoxin, IFN-gamma, or phorbol ester.

C8 binding protein (C8bp) is a 65-kDa membrane glycoprotein that inhibits complement-mediated lysis by homologous C5b-9. C8bp was first identified on human erythrocytes, but could also be detected on peripheral blood cells, platelets, glomerular cells and synovial fibroblasts. Lack of C8bp as seen in patients with paroxysmal nocturnal hemoglobinuria type III results in enhanced susceptibility of the cells toward C5b-9. We studied C8bp expression on the promonocytic cell line U937. In addition to the membrane-bound C8bp, a cytoplasmic form of C8bp could also be identified by immunofluorescence, blotting, and precipitation. Stimulation of the cells with IL-1 beta, endotoxin, IFN-gamma, or phorbol ester increased C8bp surface expression. Because cycloheximide did not inhibit enhanced surface expression, it was most probably mobilized from cytoplasmic reservoirs. Thus, resistance of nuclear cells to complement attack seems to be based on two events: 1) the removal of the C5b-9 complex from the membrane; and 2) expression of regulatory surface proteins such as C8bp, which inhibit C5b-9-mediated lysis. We propose that the C8bp mobilization by cytokines might provide an additional protection against complement attack by its known interference with the C5b-9 assembly.

Blood Proteins↗
PubMed1992

Genetic polymorphism of complement component C6, C7 and C8(1) in Chinese Han population in northeast China.

Distributions of complement phenotypes, C6, C7, and C8(1) were studied using thin agarose gel isoelectric focusing (AGIEF) or ultra-thin polyacrylamide gel isoelectric focusing (PAGIEF) and subsequent immunoblotting techniques in 203 Chinese Han population in Liaoning Province of northeast China. The gene frequencies were as follows: C6*A 0.4704, C6*B 0.5049, C6*B2 0.0148, C6*B3 0.0049, and C6*M 0.0049; C7*1 0.8251, C7*2 0.1108, C7*3 0.0320, and C7*4 0.0320; C8(1)*A 0.5567 and C8(1)B 0.4433, respectively. All the observed numbers of the phenotypes were in agreement with the expected numbers under the Hardy-Weinberg equilibrium. The gene frequencies among Chinese subpopulations and other various populations were compared.

Asian People↗
PubMed1991

Human umbilical vein endothelial cells synthesize functional C3, C5, C6, C8 and C9 in vitro.

Human endothelial cells (EC), cultured serum-free, synthesize de novo protein which increasingly bind to agarose beads (an alternative pathway activator), until a plateau phase is reached after 24-48 h. EC synthesize functional C3, C5, C6, C8 and C9, which were detected on co-cultured agarose beads, using relevant polyclonal anti-complement antibodies. Two monoclonal anti-C9 neoepitope antibodies (aE11, poly C9-MA) bound to the co-cultured beads, showing that the terminal complement complex (TCC) (C5b-9) was assembled on the beads. This also suggests that C7 is synthesized. There seems to be a positive correlation between the amount of agarose-bound labelled protein and agarose-bound complement. The results indicate that EC produce and secrete the components for the functional alternative and terminal pathways of complement.

Antibodies, Monoclonal↗
PubMed1992

Complement component deficiencies and infection: C5, C8 and C3 deficiencies in three families.

Three families are described with complement component deficiencies. In one family, five children had C5 deficiency; in a second family, two children had C8 deficiency and one child in a third family had C3 deficiency. The index cases were identified during screening of patients with recurrent pyogenic infections, recurrent meningitis and meningococcaemia. Two of the five C5 deficient patients had recurrent meningitis and meningococcaemia, two had recurrent respiratory tract infections and otitis and one was healthy. One of the C8 deficient patients had meningitis, meningococcaemia and pneumonia, whereas his sibling with the same deficiency was healthy. The patient with C3 deficiency had four episodes of meningitis and recurrent otitis.

Child↗
PubMed1991

Gene responsible for deficient activity of the beta subunit of C8, the eighth component of complement, is located on mouse chromosome 4.

Sera from 73 strains of mice were tested for hemolytic activity through the classical and the alternative pathways (CP and AP) in a single radial hemolysis assay. Sera from 16 out of 45 laboratory inbred strains had no lytic activity, and Ouchterlony analysis with anti-C5 serum showed them to be C5-deficient. Sera from 2 out of 28 strains derived from wild mice also had no lytic activity, but the C5 molecule was detectable in both. The hemolytic activity of sera from these strains can be restored by the addition of partially purified human C8 or human serum deficient in C8 alpha-gamma, leading us to conclude that strains M.MOL-MSM (MSM) and Mae are deficient in the beta subunit of C8. Typing of (DBA/2J X MSM)F1 hybrids and of progeny of a backcross to MSM showed that this C8 deficiency is controlled by a single recessive gene, designated C8b; the allele with hemolytic activity is C8b1; and the allele with no activity C8b0. Because of synteny homologies in mouse and human, we looked for and found close linkage between C8b and Pgm-2. Typing of recombinant mice for Mup-1 mapped the C8b locus 2.3 centimorgans (cM) telomeric to Pgm-2 on mouse chromosome 4.

Animals↗
PubMed1979

Host defense against Neisseria meningitidis requires a complement-dependent bactericidal activity.

Some individuals, with severe or recurrent infection with Neisseria species, have been identified as lacking a component in the terminal attack sequence of complement (complement components 5 to 9). The relevance of the terminal attack sequence to various phases of host defense was tested with the use of the C-11 strain of meningococci and human serum genetically deficient in complement component 8 (C8-D). The C8-D serum was comparable to normal serum in supporting ingestion and intracellular killing by leukocytes but was not bactericidal in the fluid phase unless reconstituted with C8. Thus, serum complement-dependent bactericidal activity may be especially critical for the host's defense against invasive Neisseria species.

Blood Bactericidal Activity↗
PubMed1976

Abnormalities of complement and its components in patients with acute leukemia, Hodgkin's disease, and sarcoma.

Whole complement and component titers were measured in patients with acute leukemia, Hodgkin's disease, and sarcoma. Serum samples were obtained from 42 consecutive patients and 11 healthy control subjects. Sera were frozen and maintained at -70 degrees until analyzed by hemolytic assay. Titers were normalized using a titer obtained from a single source of pooled human serum analyzed simultaneously with each patient sample to correct for day-to-day variation inherent in the assay technique. Significant elevations (p less than or equal to 0.05) of whole complement and C5, C8, and C9 were observed for each patient category, compared to controls. Forty-one of 42 patients had C9 titers greater than or equal to 2 S.D. above the mean titer for controls. Mean C3 and C7 titers were not elevated or depressed in any group. No clinical factors that correlated with abnormal complement or component titers were identified.

Adolescent↗
PubMed1990

Myelin basic protein is affected by reduced synthesis of myelin proteolipid protein in the jimpy mouse.

Myelin basic proteins (MBPs) from 6-day-old, 10-day-old, 20-day-old and adult normal mouse brain were compared with those from 20-day-old jimpy (dysmyelinating mutant) mouse brain to determine the effect of reduced levels of proteolipid protein (PLP) on MBPs. Alkaline-urea-gel electrophoresis showed that 6-day-old and 10-day-old normal and jimpy MBPs lacked charge microheterogeneity, since C8 (the least cationic of the components; not be confused with complement component C8) was the only charge isomer present. In contrast, MBPs from 20-day-old and adult normal mouse brain displayed extensive charge microheterogeneity, having at least eight components. A 32 kDa MBP was the major isoform observed on immunoblots of acid-soluble protein from 6-day-old and 10-day-old normal and 20-day-old jimpy mouse brain. There were eight bands present in 20-day-old and adult normal mouse brain. Purified human MBP charge heteromers C1, C2, C3 and C4 reacted strongly with rat 14 kDa MBP antiserum, whereas the reaction with human C8 was weak. This suggested that MBPs from early-myelinating and jimpy mice did not react to MBP antisera because C8 was the major charge isomer in these animals. Purification of MBPs from normal and jimpy brain by alkaline-gel electrophoresis showed that both normal and jimpy MBPs have size heterogeneity when subjected to SDS/PAGE. However, the size isoforms in normal mouse brain (32, 21, 18.5, 17 and 14 kDa) differed from those in jimpy brain (32, 21, 20, 17, 15 and 14 kDa) in both size and relative amounts. Amino acid analyses of MBPs from jimpy brain showed an increase in glutamic acid, alanine and ornithine, and a decrease in histidine, arginine and proline. The changes in glutamic acid, ornithine and arginine are characteristic of the differences observed in human C8 when compared with C1.

Aging↗
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↗
PubMed1978

Differences in the terminal steps of complement lysis of normal and paroxysmal nocturnal hemoglobinuria red cells.

The number of microscopically visible lesions produced on the membrane for a given degree of lysis on normal cells as on PNH cells. Since complement lesions were not formed until C8 or C9 was incorporated into the complement sequence, the results suggest that increased lysis of red cells in PNH is due at least in part to more efficient penetration of the PNH membrane by the terminal lytic sequence of complement. Furthermore, the efficiency of the terminal lytic sequence in the lysis of PNH cells when complement was activated by the alternative pathway and the classical pathway was analyzed. There was no significant difference (p less than 0.01) in the number of lesion present at an equivalent degree of lysis when initiated by antibody, cobra venom factor, or acidification. Thus, the efficiency of the terminal lytic sequence does not vary with different modes of activation.

Complement C8↗
PubMed1976

Increased ion permeability of planar lipid bilayer membranes after treatment with the C5b-9 cytolytic attack mechanism of complement.

The ion permeability of planar lipid bilayers, as measured electrically, was found to increase modestly upon treatment with purified complement complex C5b,6 and complement components C7 and C8. The subsequent addition C9 greatly amplified this change. No permeability changes occurred when components were added individually to the membrane, or when they were used in paired combinations, or when C5b, C7, C8, and C9 were admixed prior to addition. Thus, there is a significant parallel between the permeability changes induced in the model membrane and damage produced in biological membranes by the C5b-9 complement attack sequence. The efficiency of membrane action by C5b-9 was critically dependent on the order in whcih components were added to the membrane. There were also differences in the electrical properties of membranes treated with C5b-8 and C5b-9, though in both cases the enhanced bilayer permeability is best attributed to the formation of trans-membrane channels. Collectively, the data are consistent with the hypothesis that the mechanism of membrane action by complement involves the production of a stable channel across the lipid bilayer, resulting in cell death by colloid-osmotic lysis.

Cell Membrane Permeability↗