Three biochemical pathways activate the complement system: the classical complement pathway, the alternative complement pathway, and the lectin pathway. (wikipedia.org)
The classical complement pathway typically requires antigen-antibody complexes for activation (specific immune response), whereas the alternative pathway can be activated by spontaneous complement component 3 (C3) hydrolysis, foreign material, pathogens, or damaged cells. (wikipedia.org)
Deficiencies of an early component of the classical complement pathway (C1q, C1r, C1s, C2, C4) have been associated with lupus like autoimmune conditions. (mastattack.org)
Immunization2
Upon immunization with an antigen, more of these receptors are formed, and they are then shed from the cells to circulate in the blood. (wikipedia.org)
or actively by prior immunization of the recipient with graft antigens which evoke specific antibodies and form antigen-antibody complexes which bind to the antigen receptor sites of the T-cells and block their cytotoxic activity. (lookformedical.com)
Inflammation7
The complement system, also known as complement cascade, is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. (wikipedia.org)
The end result of this complement activation or complement fixation cascade is stimulation of phagocytes to clear foreign and damaged material, inflammation to attract additional phagocytes, and activation of the cell-killing membrane attack complex. (wikipedia.org)
In this review we discuss current evidence that complement activation contributes to progression of CKD, how complement could cause renal inflammation and whether complement inhibition would slow progression of renal disease. (wjgnet.com)
Complement activation occurs in progressive chronic kidney disease and may contribute to the chronic inflammation that is characteristically found in the kidney. (wjgnet.com)
It is therefore possible that inhibiting complement activation would reduce inflammation, lead to reduced fibrosis and preservation of renal function. (wjgnet.com)
The reason for this is that these proteins help to clean up large groups of molecules called immune complexes before they can cause inflammation. (mastattack.org)
Humoral2
An immune response with both cellular and humoral components, directed against an allogeneic transplant, whose tissue antigens are not compatible with those of the recipient. (lookformedical.com)
The innate immune system comprises physical, chemical, and biological barriers (e.g., the skin , gastric acid , commensal organisms ) and both cellular (e.g., granulocytes , natural killer cells , mast cells ) and humoral ( complement system ) defense mechanisms . (amboss.com)
Immune9
The complement system can, however, be recruited and brought into action by antibodies generated by the adaptive immune system. (wikipedia.org)
Ehrlich introduced the term "complement" as part of his larger theory of the immune system. (wikipedia.org)
According to this theory, the immune system consists of cells that have specific receptors on their surface to recognize antigens. (wikipedia.org)
Ehrlich, therefore, named this heat-labile component "complement", because it is something in the blood that "complements" the cells of the immune system. (wikipedia.org)
citation needed] Complement triggers the following immune functions: Membrane attack - by rupturing the cell wall of bacteria. (wikipedia.org)
The complement system is an integral part of the innate immune system but also augments adaptive immune responses. (wjgnet.com)
Without these proteins, immune complexes and dead cells are not removed and cause local irritation. (mastattack.org)
However, HAE patients have been shown to have a normal level of immune complexes. (mastattack.org)
The innate immune system develops in utero and, unlike the adaptive (acquired) immune system , does not require imprinting or adaptation to specific antigens nor does it provide permanent pathogen -specific immunity . (amboss.com)
Proteins5
The complement system consists of a number of small proteins that are synthesized by the liver, and circulate in the blood as inactive precursors. (wikipedia.org)
About 50 proteins and protein fragments make up the complement system, including serum proteins, and cell membrane receptors. (wikipedia.org)
Lectin pathway) Most of the proteins and glycoproteins that constitute the complement system are synthesized by hepatocytes. (wikipedia.org)
In HAE types I and II, complement proteins C2 and C4 are low. (mastattack.org)
Those receptors, which we now call "antibodies", were called by Ehrlich "amboceptors" to emphasise their bifunctional binding capacity: They recognise and bind to a specific antigen, but they also recognise and bind to the heat-labile antimicrobial component of fresh serum. (wikipedia.org)
Recognize1
Activated B cells and memory T cells can recognize specific antigens on pathogens. (amboss.com)
Specific3
Ehrlich believed that each antigen-specific amboceptor has its own specific complement, whereas Bordet believed that there is only one type of complement. (wikipedia.org)
In the early 20th century, this controversy was resolved when it became understood that complement can act in combination with specific antibodies, or on its own in a non-specific way. (wikipedia.org)
It may be nonspecific as in the administration of immunosuppressive agents (drugs or radiation) or by lymphocyte depletion or may be specific as in desensitization or the simultaneous administration of antigen and immunosuppressive drugs. (lookformedical.com)
Rejection2
Complement activation is known to occur in many diverse renal diseases, including glomerulonephritis, thrombotic microangiopathies and transplant rejection. (wjgnet.com)
Donor and recipient pairs should be of identical ABO blood group, and in addition should be matched as closely as possible for HISTOCOMPATIBILITY ANTIGENS in order to minimize the likelihood of allograft rejection. (lookformedical.com)