Search results for "complement pathway"
showing 10 items of 70 documents
The second component of human complement: Detection of two hemolytic forms in plasma by pH Variation
1988
The second component of human complement (C2) in pseudoglobulin prepared from normal plasma eluted as a single peak at high conductivity (30 mS) and pH 4.5 from the cationic exchangers S-Sepharose or Mono S in the Fast Protein Liquid Chromatography (FPLC) System. The C2 was stable at pH 4.5 and 0 degrees C if enzyme inhibitors were used and the pH was raised to 6.0 after elution from the columns. After rechromatography on Mono S in the FPLC System at the median isoelectric point of 5.5 or pH 6.0, the C2 eluted as two distinct hemolytic forms: the first peaked at 16 mS, the second at 30 mS. The two forms of C2 did not correlate with the allotypic variant of C2 in individual, normal human pla…
The Anaphylatoxic Peptide C3a of Guinea Pig Complement
1978
Abstract Highly purified guinea pig C3a was obtained after specific cleavage of isolated C3 by the alternative pathway enzyme VF-B in a one step procedure. It turned out to be a low molecular weight peptide with basic character (M.W. 9500; isoelectric point above 9.4). C3a represents an antigenetic determinant of its own in the native C3 molecule, different from the B determinant. Guinea pig C3a is resistant to 100°C for 10 minutes. Its smooth muscle contracting activity can be destroyed by trypsin and carboxypeptidase B. These findings indicate that guinea pig C3a is quite similar to human C3a.
C1q
2000
Publisher Summary This chapter provides information to the physical properties, structure, and function of C1q protein. This protein is made up of three individual polypeptide chains, A, B and C, which are synthesized as pre-molecules with 22, 25, and 28 amino acid leader sequences, respectively. C1q has a characteristic appearance under the electron microscope, with six globular heads connected by six collagen-like stalks forming a central fibril stem. Glucosylgalactosyl disaccharide units are linked to certain hydroxylysine residues in the collagen regions of all three chains. C1q has a critical function in host defense and clearance of immune complexes. Antibody-independent activation of…
Analysis of the Immune Status in Latvian Chernobyl Clean-up Workers with Nononcological Thyroid Diseases
2001
The aim of the present work was to characterize the immune status of 385 individuals who participated in the 1986–90 clean-up work of the after effects of the Chernobyl nuclear power plant explosion. Fifty-nine Chernobyl clean-up workers developed the most common thyroid diseases; euthyroid nodular and diffuse goiter; 47 healthy blood donors were taken as controls. The levels of immunoglobulins (IgA, IgG and IgM), the numbers of peripheral blood leukocytes, lymphocytes, monocytes, T lymphocytes and their subpopulations (CD3+, CD4+, CD8+), B lymphocytes (CD19+), natural killer (NK) cells (CD16+), classical and alternative pathway activity of complement (CH50, APH50), the C3 split product C3d…
Complement Protein C1q Binds to Hyaluronic Acid in the Malignant Pleural Mesothelioma Microenvironment and Promotes Tumor Growth
2017
C1q is the first recognition subcomponent of the complement classical pathway, which acts towards the clearance of pathogens and apoptotic cells. C1q is also known to modulate a range of functions of immune and non-immune cells, including their involvement in placental development and sensorial synaptic pruning. We have recently shown that C1q can promote tumour by encouraging their adhesion, migration and proliferation in addition to angiogenesis and metastasis. In this study, we have examined the role of C1q in the microenvironment of malignant pleuric mesothelioma (MPM), a rare form of cancer commonly associated with exposure to asbestos. We found that C1q was highly expressed in all MPM…
Is the Complement Protein C1q a Pro- or Anti-tumorigenic Factor? Bioinformatics Analysis Involving Human Carcinomas
2019
C1q is the first subcomponent of the classical pathway of the complement system and belongs to the C1q/Tumor Necrosis Factor superfamily. C1q can perform a diverse range of immune and non-immune functions in a complement-dependent as well as -independent manner. Being a pattern recognition molecule of the innate immunity, C1q can recognize a number of self, non-self and altered-self ligands and bring about effector mechanisms designed to clear pathogens via opsonisation and inflammatory response. C1q is locally synthesized by macrophages and dendritic cells, and thus, can get involved in a range of biological processes, such as angiogenesis and tissue remodeling, immune modulation, and immu…
Monoclonal antibodies against components of the classical pathway of complement.
1989
Activation of the classical pathway of complement involves several binding and enzymatic cleavage processes. Binding and enzymatic activation results in the appearance of new structures in the individual components. This report describes the different activation steps for C1q, C1r, C1s, C4 and C2 and summarizes monoclonal antibodies reported so far which recognize either conserved epitopes or activation-dependent epitopes with particular emphasis on neoepitopes occurring during the activation cascade.
C1q-bearing immune complexes detected by a monoclonal antibody to human C1q in rheumatoid arthritis sera and synovial fluids
1991
Using a monoclonal antibody directed against the C-chain of human C1q, we detected C1q-bearing immune complexes (IC) in sera and synovial fluids of rheumatoid arthritis (RA) patients. In a sandwich-ELISA, C1q-bearing IC were captured by the solid-phase monoclonal antibody and then detected with peroxidase-labeled F(ab')2-antibodies to either human IgG or IgM. The results of this assay were compared to an ELISA-modification of the C1q-solid-phase binding assay (C1q-SPBA). C1q-bearing IC were detected in 81.1% of RA-sera and the 65.2% of RA-synovial fluids. IgG as well as IgM was present in 72.6% of the sera and 70% of the synovial fluids which were positive in both assays. Most RA sera that …
Studies on the mechanism of PMN activation II. by triggering the alternative pathway of complement activation
1982
By means of cobra venom factor (CVF) it is demonstrated that the stimulation of hexosemonophosphate shunt (HMPS) of human polymorphonuclear leukocytes (PMN) by zymosan (Z) and dextran sulfate (DS) is caused by at least two modes of activation: (a) via activation caused by phagocytosis, (b) via activated alternative pathway of complement activation (APC). Active factors of APC presented with phagocytizable objects strongly enhance activation of PMN. The effect of APC can be observed in serum-containing as well as in serum-free cultures. It can be demonstrated that in serum-free cultures the factors of APC participating in the activation of PMN are supplied by monocytes. By the use of synthet…
Mechanism of reperfusion damage after thrombolysis and ‘direct PTCA’
1997
Summary There is general agreement between cardiologists, that reperfusion of the infarct related coronary artery (PTCA) is the method of choice for the treatment of an acute myocardial infarction. However, the method utilized for inducing a rapid and complete reperfusion is still discussed. Even if thrombolysis will remain the method of choice for the major part of the population, part of the patient cohort with acute infarction will be treated by direct PTCA. Rapid reperfusion of ischemic myocardium reduces infarct size by limiting infarct extension into the entire area at risk, although a reperfusion damage is induced in the core ischemic area. This reperfusion damage has been convincing…