No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Assay and Properties of Serum Inhibitor of C'1-Esterase
Abstract
An assay is described for measurement of a serum inhibitor of an esterase derived from preparations of the first component of complement (C'1-esterase). Esterolysis of N-acetyl-L-tyrosine ethyl ester by C'1-esterase is inhibited instantaneously and stoichiometrically by fresh human serum. Units of C'1-esterase and of serum inhibitor are defined. The inhibitor in human serum is stable at 45 for at least 4 months, at 37° for at least 24 hr. and at 48° for at least 30 min. It is completely inactivated during 30 min. incubation at 60° and is labile at 0° at pH values below 6. The inhibitor is inactivated at —5 in the presence of methanol concentrations of 15° or greater but is recovered quantitatively in a 40° ammonium sulfate supernatant fraction. These data are being applied to purification of the inhibitor from human serum. Purification procedures and properties of the purified inhibitor will be reported elsewhere.
... ester, and of interacting with C'4 and possibly C'2. Human and various other serums contain a naturally occurring inhibitor, a heat-labile a2-globulin, which can block, under appropriate conditions, both the esterolytic and complement-interacting properties of Cq esterase (6)(7)(8)(9). The inhibitor, partially purified from human serum by ammonium sulfate fractionation and column chromatography, contains only small amounts of serum trypsin and plasmin inhibitors (8). ...
... Activity and solubility were unimpaired by storage for at least 1 month. One unit of C'I esterase is defined as that amount of enzyme which will liberate 0.5 micromol of fitratable acid during incubation for 15 minutes at 37 ° with N-acetyl-L-tyrosine ethyl ester under standardized conditions of assay (6,7). The preparation of Cq esterase used contained 30 #g. of nitrogen per unit of enzyme. ...
... Activity and solubility were unimpaired by storage for at least several months. One unit of inhibitor stoichiometricaily inhibits the esterolytic activity of 10 units of C'I esterase under standardized conditions of assay (7). The preparation of inhibitor used contained 8 #g. of nitrogen per unit. ...
A model system for the investigation of immune cellular injury in primary isolates of a fixed-tissue cell of human origin has been described, using metabolism-inhibition and uptake of trypan blue as independent criteria of cytoxicity. Cytotoxic effects on human amnion cells were produced by the combination of specific rabbit antibody and factors in normal human serum which were indistinguishable from the components of hemolytic complement and calcium and magnesium ions. The data have been discussed in relation to the apparent multiplicity of serologic systems which can effect cellular injury. The nature of the cell and the source of antibody or normal serum constituents have been emphasized as factors which may influence the experimental selection of a given humoral mechanism.
... During the initial investigations that resulted in the isolation and characterization of C1, human serum was found to contain a heat sensitive substance that inhibited the enzymatic activity of C1. This inhibitory activity, termed CI esterase inhibitor, was further defined by Lepow [4] and was first isolated by Pensky et al. [5]. Several methods have been described for the purification of C1esterase inhibitor involving Polyethylene Glycol (PEG) precipitation [6,7] or affinity chromatography or by using multiple chromatography steps [8][9][10][11]. ...
... There are many reports of purification of C1-INH protein [4][5][6]8,10,12,13] and these previously published reports detail the usage of precipitation and affinity chromatography methods for purification of C1-INH and some of them have problem with low yields, time consuming process and does not result in pure protein of therapeutic grade. In the current research, an attempt was made to look for a purification scheme that is both economical and scalable for the purification of C1-esterase inhibitor, without compromising on yields, purity and its other therapeutic characteristics. ...
... esterolytic activity of C'l-esterase was measured using 5r-acetyl-L-tyrosine ethyl ester as substrate. One unit of C'1 esterase is defined as that amount which liberates 0.5 micromole of H + in 15 minutes at 37°C as detected by microformol titration with 0.05 N NaOH (32,33). ...
... The entire 2.375 ml of reaction mixture was then assayed by addition at 37°C of 0.125 ml of 1 M N-acetyl-r.-tyrosine ethyl ester in methyl cellosolve and performing microformol titrations with 0.05 N NaOH on 1.0 ml aliquots removed at 0 and 15 minutes. The results are expressed as units of CI1 esterase per 1.0 ml aliquot, where 1 unit corresponds to the liberation of 0.5 micromole of H + (32,33). ...
A euglobulin fraction of human C'1 has been chromatographically resolved into three distinct activities, designated C'1q, C'1r, and C'1s, in the order of their elution from DEAE cellulose. All three of these activities have been shown to participate in various hemolytic reactions requiring C'1, including the cold phase of the Donath-Landsteiner reaction, and to be necessary for generation of C'1 esterase. C'1q was identical with a previously described serum protein implicated in a very early step of complement action and designated the 11S component on the basis of its sedimentation constant. C'1r could not be related to a known complement activity and has been presented as a new component. C'1s, on the basis of chromatographic evidence, was identified with C'1 proesterase. Methods of assay of these components of C'1 have been presented.
The significance of C'1q, C'1r, and C'1s in generation of C'1 esterase and the central role of this enzyme in reactions involving C'1, C'4, and C'2 have been discussed.
... C1 inactivator was purified from human serum according to the method of Pensky (7,18) and its activity measured using acetyl tyrosine ethyl ester as the substrate for purified Cis as has been previously described (53,54). No c~2-macroglobulin was detectable by immunodiffusion in the Ci inactivator preparations, nor did these preparations display trypsin inhibitory activity in the BAPNA assay (20). ...
... This thesis was suggested by the study of individuals with hereditary angioneurotic edema who have a deficiency of a specific heatand acid-labile a2-neuraminoglycoprotein designated CI inactivator (5-7, 42, 64). Although Ci inactivator effectively inhibits both kallikrein, PF/dil and Ci in purified systems (9,54), the experimental evidence now available suggests that activation of kallikrein and the permeability globulin system, if it occurs in hereditary angioneurotic edema, is not proportionately as great as is the activation of the complement system (12). ...
Activation of plasma kallikrein arginine esterase activity by kaolin resulted in peak activity at 1 min of incubation and a 50% reduction in activity at 5 min in normal plasma, and 30% reduction in the plasma of patients with hereditary angioneurotic edema who lacked the C1 inactivator. The peak esterolytic activity was inhibited by soybean trypsin inhibitor whereas the 5 min activity was resistant to this inhibitor. Acid treatment of normal and hereditary angioneurotic edema plasma destroyed the factor responsible for the fall in esterase activity at 5 min and the factor which rendered the esterase resistant to soybean trypsin inhibitor. Purified α2-macroglobulin inhibited approximately 50% of the TAMe esterase activity of purified plasma kallikrein without changing its activity toward basic amino acid esters. The interaction between the α2-macroglobulin and kallikrein resulted in alterations in the gel filtration chromatographic pattern of the TAMe esterase and biologic activity of kallikrein, indicating that kallikrein was bound to the α2-macroglobulin. The TAMe esterase activity of this complex, isolated by column chromatography, was resistant to C1 inactivator and SBTI. Studies of incubation mixtures of kallikrein, α2-macroglobulin and C1 inactivator suggested that these inhibitors compete for the enzyme, and that the α2-macroglobulin partially protects the esterase activity of kallikrein from C1 inactivator. The α2-macroglobulin isolated from kaolin-activated plasma possessed 240 times the esterolytic activity of the α2-macroglobulin purified from plasma treated with inhibitors of kallikrein and of its activation. The α2-macroglobulin blocked the uterine-containing activity and vascular permeability-inducing effects of plasma kallikrein. These studies suggest that the α2-macroglobulin is a major plasma inhibitor of kallikrein and provide a new example of an interrelationship between the coagulation, fibrinolytic, and kallikrein enzyme systems.
... Tamura and Nelson (1967) studied complement inhibitors in guinea pig and rabbit serum. These included C1 inhibitor, which is well known (Levy and Lepow, 1959), an inhibitor of C6 which probably does not exist but could have been a C567 uptake inhibitor, such as vitronectin, and a C3 inhibitor which they showed to inhibit lysis and immune adherence. This molecule was probably Factor I but could also have been Factor H on the basis of purification data, or probably a mixture of the two. ...
Factor I was first discovered in 1966. Its importance became apparent with the description of the original Factor I deficient patient in Boston in 1967. This patient presented with a hyperactive alternative complement pathway resulting in secondary complement deficiency due to continuous complement consumption. On the basis of these findings, the mechanism of the alternative pathway was worked out. In 1975, the surprise finding was made that elevating levels of Factor I in plasma down-regulated the alternative pathway. Attempts to exploit this finding for clinical use had a long and frustrating history and it was not until 2019 that the first patient was treated with the gene therapy vector for age related macular degeneration by Professor Sir Robert MacLaren in Oxford. This review follows the long and contorted course from initial observations to clinical use of complement Factor I.
... Once the major components of the system could be detected and assayed individually, it became possible to detect regulatory proteins, and later cell-surface-bound receptors and regulators. C1 inhibitor was described by Levy and Lepow, (1959), and association of its deficiency with hereditary angio-edema was shown in 1962. (Landerman et al., 1962;Donaldson and Evans, 1962). ...
The complement system has been studied for about 120 years. Progress in defining this large and complex system has been dependent on the research technologies available, but since the introduction of protein chromatography, electrophoresis, and antibody-based assay methods in the 1950s and 60s, and sequencing of proteins and DNA in the 70 s and 80s, there has been very rapid accumulation of data. With more recent improvements in 3D structure determination (nmr and X-ray crystallography), the structures of most of the complement proteins have now been solved. Complement research since 1990 has been greatly stimulated by the discoveries of the multiple proteins in the lectin pathway, the strong association of Factor H, C3, Factor B allelic variants with adult macular degeneration and atypical haemolytic uremic syndrome, and the introduction of the anti-C5 monoclonal antibody as a therapy for paroxysmal nocturnal hemoglobinuria and atypical haemolytic uremic syndrome. Potential new roles for complement in tissue development and the search for novel therapeutics suggest a very active future for complement research
... In 1917, Crowder and Crowder were the first to point at the autosomal-dominant mode of inheritance of hereditary angioedema [22], which was supported by others [23,24]. Although Lepow's group has already disclosed the biochemical nature of C1-INH in 1959 [107], and further studies pointed at the importance of this inhibitor and the consequences of its deficiency, the genetic coding for C1-INH was fully disclosed only in the mid-1980s. A comprehensive description of the structure, chromosomal location of the C1-INH gene (SERPING1), and cDNA cloning was presented in 1986 by Bock et al. [108]. ...
The term “swelling” has been used in the old scriptures to illustrate a change of normal figure and, as such, an expression of illness. It should be noted that in ancient times, human diseases were very often regarded a punishment from God. Hence, it is not surprising that one of the oldest tests for infidelity involved swelling as an inflicted punishment. The great Greek physician Hippocrates (377–460 BC), considered one of the most outstanding figures in the history of medicine and “Father of the Western Medicine,” already used the term oídēma to describe swelling of organs. It took many centuries later until the first description of angioedema as a distinct medical entity was minted by Quinke in 1882. The historical progression in angioedema research has been characterized by intermittent “leaps” in interest and scientific achievements. As an example, it took 75 years from the accurate description of hereditary angioedema (HAE) by Osler (1888), until a group of researchers headed by Donaldson (1963) disclosed the central role of C1 inhibitor in angioedema pathophysiology. What followed was a result of a collective effort by many researchers and scientific groups who were able to elucidate the intricate connections between the implicated biochemical pathways. Still, scientific progress was hardly translated into effective therapy, and another 45 years had to elapse until the renewed interest in HAE was boosted by studies on the efficacy and safety of novel therapies about 10 years ago. In the twenty-first century, HAE ceased to be an “orphan disease” and its future is far more optimistic. It is better managed now by specialized angioedema centers, harmonized clinical guidelines, educational programs, laboratory services, and continued basic and clinical research. Patient associations worldwide are offering support and guidance, and governments and healthcare systems are gradually addressing patient and family needs.
... An inhibitor of activated C1 Levy and Lepow, 1959) controls the initial activation of the classical pathway and controls the production of the EACill-associated polypeptide kininlike substance which induces changes in vascular permeability (Donaldson et al., 1969). Hereditary angioedema is a disease characterized by recurrent subepithelial swelling of the skin and mucous membranes (Donaldson and Evans, 1963) and has been shown to be associated with a genetic deficiency of the C1 inhibitor. ...
The ability of a host to survive the invasion of microorganisms and other foreign particles resides mainly with the immune system. It is generally accepted today that the immune response is composed of humoral and cellular arms which act either individually or in concert to eliminate the foreign material. The humoral arm of the immune response includes antibodies, complement, and various soluble lymphocyte products (lymphokines), while the cellular arm is comprised of the various cell types of the reticuloendothelial system. The effector functions of the cellular and humoral arms of the immune response are generally beneficial to the host, although some localized tissue damage may result in addition to or as a consequence of the destruction and elimination of foreign materials. In certain autoimmune disorders, the immune system fails to distinguish between self and non-self and directs its activity against the host.
... On a functional level, C1-INH was characterized in the 1950s by Lepow et al. [169], Levy and Lepow [171], and Ratnoff and Lepow [244]. Immunochemically, C1-INH was first recognized as an c:x2-neuraminoglycoprotein [266]. ...
... Total hemolytic complement was determined according to the method of Mayer (4). C1 esterase inhibitor (Cls INH) was determined according to the method of Levy and Lepow (5). The other C components were determined by electroimmunoassay as described previously (6). ...
This paper describes the third case of C3b inactivator (factor I) deficiency in a turkish child.
... The inhibitor was dissolved in 0.005 phosphate buffer. One unit of C'I esterase inhibitor is that amount which neutralizes the esterolytic properties of 10 units of Cq esterase, as as~yed upon a substrate of N-acetyl-Ltyrosine ethyl ester (2). ...
The fraction of human serum designated as C'1 esterase inhibitor is known to inhibit the action of C'1 esterase, a plasma kallikrein, and PF/Dil, an enzyme in plasma enhancing cutaneous vascular permeability. In the present study, C'1 esterase inhibitor has been found to block the actions of plasmin and the C'1r subcomponent of the first component of complement, and to retard the generation of PF/Dil. No inhibition of blood clotting or of the generation of plasmin was demonstrable.
... The activity of C'1 esterase was measured in dtro by microformol titration of the add liberated from N-acetyl-~-tyrosine ethyl ester during incubation under standardized conditions (16,22). One unit of C'I esterase is defined as that amount which liberates 0.5 micromole of H + in 15 minutes at 37°C under the conditions of this assay. ...
Purified preparations of the esterase derived from the first component of complement (C'1 esterase) increased vascular permeability in guinea pig skin, an effect inhibited by triprolidine, an antihistaminic agent, but not by soy bean trypsin inhibitor. The permeability-increasing and esterolytic properties of C'1 esterase were inhibited in parallel by the serum inhibitor of C'1 esterase, diisopropylphosphofluoridate and extremes of temperature and pH. Moreover, the permeability-increasing and esterolytic properties evolved in parallel when C'1 esterase was generated from its subcomponents. How C'1 esterase induces changes in vascular permeability remains unexplained, although the possibility that its action is mediated through a histamine-like agent is attractive.
... C1 inhibitor was tested by the method of Levy and Lepow (10). C2 was detected by the ability to convert EAC 14 (human) to EAC142 which could then by lysed by EDTA complement. ...
This paper describes the characteristics of the indicator factor (I) which takes part in reactive hemolysis and its identification as the seventh component of complement. I was shown to be a beta globulin with a sediment coefficient of 5.7S and a molecular weight of about 140,000. Experiments on the depletion of I activity with anti-I antiserum or with activated R euglobulin showed that I was a late acting complement component necessary for the lysis of cells after the EAC142 stage. Complement component analysis of purified I fractions excluded all known components except C7. The physicochemical characteristics of I are compatible with published data on C7. The method of quantitation described represents a convenient method of testing for C7.
... Instead, this marked increase in serum concentration of the component which is a natural substrate would be compatible with deficient activation of Cls by Clr and consequent reduction of normal activation of C4. Similarly, the unusually high level of Cl-esterase inhibitor activity may result from an accumulation of this protein under conditions where a subcomponent deficiency precludes normal C1 activation and, therefore, reduces utilization of the inhibitor (20). However, it is important to note that Cl-esterase inhibitor levels of similar magnitude have been reported by Donaldson (21) in patients with azotemia, hypertension, and normal hemolytic serum complement. ...
The experiments presented here utilize a human serum markedly deficient in hemolytic complement activity to show that: (a) The hemolytic deficiency is the result of a selective deficiency in hemolytic C1. (b) The relative absence of hemolytic C1 is due to a profound deficit in C1r function associated with less than normal C1s protein and hemolytic function and normal C1q protein concentration and function. This deficit in C1r in the face of normal C1q suggests that different cell types are responsible for the synthesis of each of these components. (c) Whatever the basis for the deficiency of C1r function, this defect results in an inadequate association of the remaining C1 subcomponents, C1q and C1s, even in the presence of calcium ions, thus suggesting that C1r has an important role in the assembly and/or maintenance of macromolecular C1.
A radioimmunoassay (the C1-inhibitor-complex assay, INCA) is described for the detection of complexes that are composed of at least C1s and C1-inhibitor. This INCA is based on demonstrating that C1s and C1-inhibitor (C1-In) are linked: after an incubation with anti-C1s-Sepharose, bound C1sC1-In complexes are detected by 125I-anti-C1-In. C1sC1-In complexes were prepared by the addition of a slight excess of C1s to normal human serum (NHS). As little as 2 ng C1-In bound to C1s was detected. Additional free C1s in serum hardly influenced the detection of C1sC1-In complexes.
Complexes presumably composed of C1rC1s(C1-In)2 were generated by the addition of aggregated IgG to NHS. This generation was inhibited by lowering the temperature to 0 degrees C, and by EDTA, and depended on the concentration of aggregated IgG. These complexes had a sedimentation value of approximately 9S. Complexes of C1s and C1-In were also generated in NHS by the addition of DNP-albumin and protein A, but not by zymosan.
The INCA was applied to blood samples from normal donors and patients. Sixteen out of 19 samples from patients with acute glomerulonephritis contained increased amounts of C1rC1s(C1-In)2 complexes as compared with the amounts in blood samples from normal donors.
The INCA provides a useful tool to assess the activation of C1 in the presence of C1-In, both in vitro and in vivo.
Research and new tools in biomaterials development by using peptides are currently growing, as more functional and versatile building blocks are used to design a host of functional biomaterials via chemical modifications for health care applications. It is a field that is attracting researchers from across soft matter science, molecular engineering and biomaterials science.
Covering the fundamental concepts of self-assembly, design and synthesis of peptides, this book will provide a solid introduction to the field for those interested in developing functional biomaterials by using peptide derivatives. The bioactive nature of the peptides and their physical properties are discussed in various applications in biomedicine. This book will help researchers and students working in biomaterials and biomedicine fields and help their understanding of modulating biological processes for disease diagnosis and treatments.
A system in the body having as potent a biological activity as the kininogenase-kinin system requires a regulating mechanism that limits the concentration of the active principles. The activity of kininogenases can be controlled either by blocking with inhibitors or by degradation with enzymes. Under normal conditions the system is regulated with remarkable precision; in pathological states the mechanism may be overwhelmed.
With recent advances in the field of complement research, much of the newer knowledge about the technique of assay has come from application of modern tools of molecular biology to the study of immune mechanism in various chronic diseases.
In view of this, the author has carried out the studies on hemolytic complement activities and components of complement in chronic liver diseases.
Sera from the total of 186 cases consisted of 105 cases of patients with chronic hepatitis, 31 cases of liver cirrhosis, and 50 normal controls served as the material for observations by micro titer method. The mean number with standerd deviation (m±S.D.) of 50% units hemolytic complement activity (CH 50) in normal controls were showed 67.20±15.40u. In the cases of chronic liver diseases, the number in chronic hepatitis were showed 44.75±27.40u. and in liver cirrhosis 45.55±31.28u. On the between of active form and inactive form in chronic hepatitis, CH 50 in the former were showed lower levels than in the latter.
For the measurements of components, reactivity of each of the nine components (namely C1, C4, C2, C3, C5, C6, C7, C8 and C9) of complement were observed. The kind of component with lowest level in chronic hepatitis was observed as C4 in 89% out of all cases, and in liver cirrhosis as C3 in all.
Furthermore, on the complement inactivator, C1-inactivator (C1-INA) was detected in 2 cases out of 36 cases of chronic hepatitis with low CH 50. Finally, C4-inactvating factor (C4-INAF) was appeared in the cases of 92% of chronic hepatitis with low CH 50, and in 50% of liver cirrhosis with low CH 50.
Although it is still not possible to integrate completely the various components involved in the inflammatory response, we now have the capability of indicating some of the effector pathways and identifying a number of points of interaction between them. The effector pathway considered in this chapter is the complement system, an essential part of the normal immune response. It consists of a special group of normal serum proteins which on activation interact sequentially in a process of limited proteolysis with the development of active macromolecules and fragments. Appreciation of this complex system has already provided a better understanding of certain pathological processes, the introduction of new therapeutic approaches, and the development of procedures to evaluate disease activity.
The complement system is one of the body’s major innate immune defense mechanisms in vertebrates. Its function is to detect foreign bodies and promote their elimination through opsonisation or lysis. Complement proteins play an important role in the immunopathogenesis of several disorders. However, excessive complement activation does not confer more protection but instead leads to several autoimmune and inflammatory diseases. With inappropriate activation of the complement system, activated complement proteins and glycoproteins may damage both healthy and diseased tissues. Development of complement inhibitors represents an effective approach in controlling dysregulated complement activity and reducing disease severity, yet few studies have investigated the nature and role of novel complement inhibitory proteins of viral origin. Viral complement inhibitors have important implications in understanding the importance of complement inhibition and their role as a promising novel therapeutic approach in diseases caused by dysregulated complement function. In this review, we discuss the role and importance of complement inhibitors derived from several viruses in the scope of human inflammatory and autoimmune diseases.
Urticaria is characterised by wealing (localised oedema) with itching and erythema and results from localised vasodilatation and transudation of fluid from the dermal microvasculature. Deep spread of the fluid produces angio-oedema. Histologically there is dermal oedema, dilated small blood vessels and lymphatics and a sparse perivascular mixed cellular infiltrate (Ackerman 1968). The urticarial lesions usually subside within hours as the extravasated fluid is absorbed into the lymphatics. There are many precipitating causes of urticaria (Table 1) which induce a chain of events in the skin of susceptible subjects, with release of mediators which increase vascular permeability and thus cause wealing (Table 2).
This chapter describes the genetic polymorphism of human C3. A little short of a decade ago Müller–Eberhard and his associates isolated a beta globulin from normal serum and showed that it was one of the proteins comprising the classical third component of complement. With the characterization of the remaining five proteins of this group, the term C3 or third component has been reserved for the first protein of the group to be purified and characterized and the first of this group to be activated during complement fixation, formerly called beta1c -globulin. The remaining proteins of the classical third component of complement have been numbered C5 through C9, in order of their participation in full complement activation. The numbering of the first three complement components in the activation sequence, Cl, C4, and C2, persists with all the illogical force of conservative tradition
Intrinsic blood clotting, thrombolysis, plasma kinin formation and complement may be regarded as four major reactive systems which are triggered into activity when blood is exposed to noxious stimuli. The four processes do not of course rely solely on intrinsic factors, but cooperate with mechanisms available in surrounding tissues. In each of the four systems there are proteolytic enzymes, often acting in sequence, i. e. on precursors of other proteases either in their own reaction sequence or in one of the other systems. In this way, numerous functional connections inside and between systems are formed. The links between blood clotting, fibrinolysis and plasma kinin formation have been under study for many years. It is probably true to say that in vivo these reactions only rarely proceed in isolation. Only two of these connections will be mentioned here. Plasmin, a protease capable of attacking a very large number of proteins is not only responsible for the lysis of blood clots, but also intervenes in the formation of clots and kinins and in the activation of complement (Ratnoff & Naff, 1967). There is now a great deal of evidence that clotting factor XII (Hageman factor) occupies a central position as the initial step in the intrinsic sequences of blood clotting, fibrinolysis and plasma kinin formation. In recent years, evidence has been produced that factor XII or its molecular subunits may also trigger the first step in the complement sequence by catalyzing the activation of subcomponent C’1s to C’1 esterase (Donaldson, 1968a; Austen, 1971). This action of factor XII may be mediated through plasmin or plasma kallikrein.
The immunological response of the organism to a foreign antigen involves both the humoral and cellular immune system. When antigen is recognized by humoral antibodies, this recognition step is the trigger of a biological reaction mediated by the complement system. The complement system, therefore, may be considered as the effector and amplification system of the humoral immune reaction.
This chapter describes the chemical mediators of the acute inflammatory response in man. Although it is not possible to interrelate fully the diverse ingredients of the inflammatory response, it is possible to identify some of the discrete reaction pathways and to indicate a number of points of interaction. The effector systems of the acute inflammatory response considered in this chapter include the complement system, the kinin-forming sequence, certain aspects of the clotting system, and the secretion of the amines and slow-reacting substance of anaphylaxis (SRS-A) from tissue mast cells. The attraction and/or activation of cells such as polymorphonuclear neutrophilic or eosinophilic leukocytes, macrophages, lymphocytes, and platelets are considered only in relation to the mentioned primary mediator systems. The chapter discusses the complement sequence and its biologically active by-products. The complement system consists of nine distinct serum proteins which interact sequentially to mediate certain of the effects of antigen–antibody interactions. Interrelationships of the kinin-forming system with clotting and fibrinolysis are also analyzed.
Unter physiologischen Bedingungen ist nicht jedes aktivierte C1-Molekül in der Lage, die C-Reaktionssequenz fortzuführen. Im menschlichen Serum (Levy und Lepow 1959; Lepow und Leon 1962; Leon und Lepow 1962) und MeerschweinchenSerum (Klein 1960) findet sich ein Faktor, der C1-Esterase blockieren kann. Er hemmt C1s sowohl in freiem wie auch gebundenem Zustand.
Selbst bei stürmisch verlaufenden Immunreaktionen erreicht der Verbrauch an C-Aktivität nur selten Größenordnungen, die sich in einer signifikanten Depression des hämolytischen Gesamt-C-Titers niederschlagen. Eine Ausnahme machen wohl nur die Nephritiden, bei denen wegen der Größe der betroffenen Oberflächen ausnahmsweise große Mengen von Ag, Ak und C reagieren, was detailliert am Beispiel der Masugi-Nephritis bei H3 diskutiert wird. Beim Menschen beträgt z. B. die gesamte innere Oberfläche der Glomerulum-Kapillaren 1,5 m2 (!) bei einer Gesamtlänge von 25 km (Bargmann 1962). Die gleichmäßige Auskleidung dieser riesigen Oberfläche mit Ak-gebundenem C bei Nephritis läßt sich auf Abb. 71 erkennen. Es leuchtet ohne weiteres ein, daß sich die Absorption derartig großer Mengen in einem Schwund der zirkulierenden C-Menge widerspiegeln muß. Dies gilt sowohl für die experimentellen Glomerulonephritiden nach dem Verfahren von Masugi als auch für die menschlichen Nephritiden und die Nephritiden mit nephrotischen Verläufen, wie sie besonders bei Kindern auftreten. Wie nicht anders zu erwarten, führt die intrarenale Ag-Ak-Reaktion zur Aktivierung des C-Systems unter Einbeziehung aller Komponenten (vgl. H3) und folglich läßt sich der periphere Schwund des C auch bei Titration der Einzelkomponenten erfassen. Der C-Schwund ist bei dieser Krankheitsgruppe so charakteristisch, daß sogar vorgeschlagen wurde, ihn zur Beurteilung der Intensität der Immunreaktion und damit zur Beurteilung der Prognose der Nephritis zu benutzen (Lange, Wasserman und Slobody 1960).
Das hereditäre angioneurotische Ödem (HANE oder HAE) ist eine seltene, jedoch mit hoher Letalität belastete Krankheit, die autosomal dominant vererbt wird. Durch Fehlen oder Funktionsunfähigkeit eines bestimmten Proteinaseninhibitors, des C1-Inaktivators, kommt es zur Aktivierung des Komplement- und Kininsystems und dadurch klinisch zum angioneurotischen Ödem der Haut oder der inneren Organe.
The adult respiratory distress syndrome (ARDS) is a well-known complication of traumatic and septic shock. Although other different triggering events cause the development of ARDS, its pathology is surprisingly consistent. It is characterized by intestinal and alveolar edema, hypoxemia due to the intrapulmonary shunting of blood, decreased pulmonary compliance, and increased microvascular permeability in the lungs.
The bactericidal activity of serum was the key observation in the discovery of the complement system, and, accordingly, it was originally defined by that function. Even though the definition was later on for technical reasons based on the reactivity in a hemolytic system, the bactericidal activity was generally accepted as its main function in vivo. The killing of bacteria by complement was seen as a most important, or even as the decisive, factor in host defense against bacterial infections. Understandably, then, it was a great surprise when in 1919 [30] a strain of guinea pigs was discovered which was deficient in complement. Hemolysis in vitro was totally lacking in some animal sera and was greatly reduced in the others. Lytic activity was restored with heat-inactivated serum [21] but not by serum treated with yeast cells or with cobra venom factor [8]. The deficiency was ascribed to a defect in what at that time was called C3. When previously immunized, the animals were able to cope normally with bacterial infections. Their nonspecific resistance to infection was, however, greatly impaired and the opsonic capacity of their serum in vitro was reduced to about one-half of normal levels [30]. Since the strain was lost in the late 1920s, long before the then C3 was recognized to comprise the factors C3, C5, C6, C7, C8, and C9, it now is only possible to speculate on which of the C3–C9 components had specifically been missing. In any case, the loss seemed to support the theories of those scientists who regarded complement as a life-preserving system.
The capacity of plasma and serum to inhibit proteinases was recognized nearly a century ago and this phenomenon has been studied extensively since. It is not the purpose of this chapter to discuss the early work in any detail; this has been done elsewhere.1 In the last decade, the chemical identity of several plasma proteinase inhibitors has been established, leading to a great increase in knowledge of the activities and functions of these substances. Comprehensive accounts of this information are available in several monographs that have appeared in recent years.2–4 We will emphasize recent advances that promise to provide a clearer understanding of the mechanisms of action and function of proteinase inhibitors.
Introduction. The nine components1 that comprise the classical pathway constitute a family of proteins whose functions can be divided into three phases: recognition, activation, and attack. Most early work in the field focused on defining the functional activities of the various components, leading to our present concept of their reaction sequence. More recently, as modern biochemical techniques have been used to study these proteins, the physicochemical basis for their activities has begun to be elucidated.
The bactericidal activity of serum was the key observation in the observation of the complement system. The activity was since seen as the most important, if not the decisive factor in host defense against bacterial infections (see also Chap. 2.4.1). It came as a great surprise, when in 1961 a strain of rabbits devoid of lytic activity was described [40] with seemingly and resistance to bacteral infection.
In recent years, studies of genetically determined deficiencies of components of the complement (C) system have begun to yield the same crucial type of information often yielded in the past by other inborn errors of metabolism, e.g., the primary immunodeficiencies as experiments of nature. To date, the deficiencies of the complement system described in man (Tables 1 and 2) are as follows: C1-esterase inhibitor in patients with hereditary angioneurotic edema; Clq in combined immuno-deficiency states; Clr deficiencies associated with infections and a strange vascular disease with lupus-like lesions and chronic glomerulonephritis; C1s with lupus and lupus-like syndrome; C2 with systemic lupus erythematosus, lupus-like syndrome, dermatomyositis, anaphylactoid purpura, increased susceptibility to infections, Hodgkin’s disease, and discoid lupus, and recently in a patient with chronic lymphocytic leukemia and dermatitis herpetiformis; C3 with increased frequency of infections, in particular, of the pulmonary apparatus; C4 with lupus erythematosus; C5 deficiency with membranous glomerulonephritis, vasculitis, arthritis, and propensity to bacterial infections; C5 abnormality with Leiner’s syndrome, recurrent and persistent gram-negative bacterial skin disease and gastroenteritis; C6 in one individual who is apparently healthy at the moment and in another with repeated episodes of meningococcal meningitis; C7 with Raynaud’s phenomenon; C7 inactivator with apparent good health; C8 deficiency with prolonged disseminated gonococcal infection syndrome, and also in three homozygous C8-deficient siblings in a family in which xeroderma pigmentosa is also present.
Complement research has evolved from the description and discovery of the plasma proteins that make up the system to a new period in which understanding of the relationships of specific fine structural data to functions is being achieved. A few complement protein fragments have been sequenced, as have several key portions of other components. Only as a result of the existence of extensive functional knowledge and specific assays could this new structural knowledge accumulate. Amino acid sequential analyses of more of these important plasma proteins will soon be accomplished by several groups, and detailed knowledge by crystallographic technique is in sight. Furthermore, these biochemical analyses have led to improved insight into the control of certain physiological and biological activities related to this system. The primary goal of most research in this area is pharmacological and/or physiological manipulation of the system to promote beneficial effects while inhibiting the injurious effects presumed to be operative in diseases of man. This goal seems to be within reach. The major good effects are those related to host defense against invading organisms. The bad effects are the tissue-destroying aspects of inflammation and cell membrane disruption. These two go hand in hand, and the goal to control one without influencing the other may sound incompatible since inflammation controls the invasion and killing of microbial organisms.
Die orthotope Lebertransplantation (OLT) ist in den letzten Jahren zu einer etablierten Methode in der Behandlung von infausten Lebererkrankungen geworden und hat deren Prognose wesentlich verbessern können. Während der Lebertransplantation kommt es immer wieder zu bedrohlichem intraoperativem Blutverlust, der sowohl die Kurz- als auch die Langzeitprognose der Lebertransplantierten entscheidend beeinflussen kann. Ziel war es, die pathophysiologischen Hämostasevorgänge bei OLT weitergehend zu untersuchen und Möglichkeiten der therapeutischen Beeinflussung zu erarbeiten. Es konnte gezeigt werden, daß sich der erhöhte Blutverlust während der anhepatischen Phase durch eine gesteigerte fibrinolytische Aktivität erklärt und daß dabei sowohl das extrinsische Fibrinolysesystem mit dem Gewebeplasminogenaktivator t-PA als auch das intrinsische Fibrinolysesystem mit urokinase-type PA (u-PA) und dem FXII-abhängigen PA beteiligt sind. Zur Bestimmung des letzteren wurde eine chromogene Substratmethode entwickelt. Venöse Stauung, Kontaktaktivierung beim Passieren des Blutes durch den veno-venösen Bypass, fehlende hepatische Clearance sind dabei die wichtigsten Auslösefaktoren. In der Reperfusionsphase konnten Zeichen einer gesteigerten Prothrombinaktivierung gemessen werden, so daß DIC-artige Hämostaseveränderungen für die postreperfusionellen Blutverluste verantwortlich gemacht werden. Eine Korrelation zur anhepatischen Fibrinolyse besteht nicht. Die Spenderleber spielt eine entscheidene Rolle bei den postreperfusionellen Hämostaseveränderungen. Leukozytäre Aktivierungsprodukte wie extrazelluläre Proteinasen und Zytokine werden aus der Spenderleber freigesetzt und stören systemisch das hämostatische Gleichgewicht. Parallel kommt es nach Reperfusion zu einer Verminderung der Thrombozytenzahl und ihrer Aggregabilität. Diese scheint partiell durch die aggregationshemmende Wirkung der University of Wisconsin Konservierungslösung bedingt zu sein, in der die Spenderleber bis zur Transplantation aufbewahrt wird. Die Gabe des Proteaseninhibitors Aprotinin scheint Hyperfibrinolysezeichen, maximalen Anstieg der t-PA Aktivität, Transfusionsbedarf und endotheliale Schäden in der Spenderleber zu reduzieren, wobei in einer offenen und randomisierten Studie der Vorteil einer kontinuierlichen Infusionsgabe gegenüber einer dreimaligen Bolusgabe deutlich wurde. In einer weiteren offenen und randomisierten Therapiestudie wurde versucht durch intraoperative Prostaglandin E1(PG E1)- Gabe endotheliale Aktivierungsprozesse in der Spenderleber zu beeinflussen. Tatsächlich führte eine PGE1-Infusion zu einem signifikant schwächeren postreperfusionellen Abfall sowohl der Thrombozytenzahl als auch der thrombozytären Aggregationsfähigkeit.
C1 inhibitor, although frequently considered primarily a complement protein, is able to inactivate proteinases that participate in several different proteolytic cascades, and is essential in the regulation of activation of both the complement system and the contact system of kinin formation. It also may serve a backup function in regulation of coagulation and of fibrinolysis. C1 inhibitor, therefore, is most important in host defense and in the mediation of vascular permeability. Its name is derived from its discovery as the inactivator of the first complement component. This came about as a result of the studies of Lepow and his colleagues in the late 1950s and early 1960s; these were directed toward the isolation of C1 and its constituent subunits: C1q, C1r and C1s1–5. C1 inhibitor was characterized as a heat labile serum protein that inhibited the esterolytic activity of C1 and its proteolytic activity against C4 and C2. It subsequently was shown to inactivate several other plasma proteases, including kallikrein, plasmin, tissue plasminogen activator, and coagulation factors XIa and XIIa (Hageman factor)5–10. The fact that C1 inhibitor inactivated proteases by formation of denaturant stable equimolar complexes was first clearly shown by Harpel and Cooper with both C1s and plasmin6. Cl inhibitor does not appear to differ in any significant way from other serpins in its mechanism of action. The P1 and P1’ residues are arginine and threonine, respectively11.
Our current knowledge of the participation of complement in human disease and its biological importance in host defense is closely connected to progress in laboratory complement diagnosis. Although it is well documented that complement plays a decissive role in the pathogenesis of various diseases, it is somewhat surprising that achievements in complement research only find limited implementation in the clinic. Despite the presence of a broad spectrum of commercially available reagents, a comprehensive analysis of complement is still performed in only a few specialized laboratories. In most clinics, complement diagnosis is confined — as it was 20 years ago — to immunochemical determinations of C3 and C4, sometimes of factor B and C1 inhibitor (C1-INH), and is only occasionally extended to hemolytic titration of total functional activity (CH50). Rare, but clinically important complement deficiency states are thus frequently overlooked. The limited acceptance of complement assays as an essential part of laboratory diagnosis in various diseases may be explained by minor therapeutic consequences, due to the lack of reagents for specific pharmacologic intervention. Recent advances in the field of complement-directed therapy is expected to influence positively clinicians’ opinion on the necessity for complement diagnosis. The management of patients with autoimmune diseases or adverse reactions to drugs and artificial surfaces or those at risk from trauma-related syndromes such as adult respiratory distress syndrome (ARDS) and multiple organ failure, benefits from early diagnosis. There is still a substantial need for laboratory parameters as early markers of deleterious clinical conditions. Longitudinal studies of patients are of advantage. The clinician can observe changes in the complement profile which may be indicative of activation resulting from disease activity or clinical intervention. The utility of complement diagnosis for monitoring of disease activity has been extensively demonstrated in cases of systemic lupus erythematosus (SLE) [12, 36, 86, 106], and elevated plasma levels of complement activation products have been shown to be of prognostic value in recognizing patients with impending transplant rejection [87] and trauma-induced adult respiratory distress syndrome and multiple organ failure [51, 178, 188]. A complete complement profile provides valuable information in diagnosing the various forms of hypocomplementemic glomerulonephritis and may substantially aid in the interpretation of findings in renal biopsies [60, 181].
Introduction: Hereditary angioedema (HAE) is a rare disorder with recurring edema formation in the subcutis and the submucosa. The growing understanding of its pathophysiology yielded a number of new orphan drugs with diverse targets and delivery routes. Because HAE is bradykinin-mediated, its pharmacotherapy focuses on inhibiting the release, or the receptor action, of this vasoactive peptide.
Areas covered: This summary is intended as a brief review of the disease and of the medicinal products (non-pathogenic and pathogenic medications) available for its therapy. It also attempts to outline the choices in its complex management, and to assist in delivering appropriate care with minimum delay. The primary objective of therapy is to prevent edema, as well as to relieve its symptoms. Nowadays, many innovative drugs are available; their efficacy and safety have been demonstrated in controlled clinical trials. C1-inhibitor concentrates, prepared from human plasma, or produced by recombinant technology, are used for supplementation. Kallikrein inhibitors block the release of bradykinin, whereas icatibant interferes with its binding to the bradykinin B2 receptor.
Expert opinion: The expansion of therapeutic alternatives allows individualized treatment supported by recent international guidelines and recommendations.
Blood levels of regulators of the complement system in preterm babies were reported in few studies only. The aim of this study was to set up a complement profile in premature and term babies focusing on the development of blood levels of MBL, key regulatory proteins and on classical pathway activity, which may allow an estimation of potential susceptibility to infection.
Complement activity (CH50), levels of mannan binding lectin (MBL), complement regulators (Factors H and I, C1 inhibitor, properdin) and C3a as marker of complement activation were assessed in three groups of healthy newborns: 1) prematures (≤ 34 weeks), 2) late prematures (>34 - <37 weeks) and 3) term neonates (≥ 37 weeks).
CH50 increased with gestational age with lower titers in cord blood than in day 5 post delivery venous blood. MBL concentrations were not significantly different among groups. Quantitative and functional C1 Inhibitor were below adult normal range in prematures <34 weeks, and lower in cord blood as compared to day 5. Factor I, factor H and properdin, remained below adult values in all groups. Low C3a levels excluded that low complement titers were due to activation-induced consumption.
These results demonstrate the relative immaturity of the complement system and its regulation, especially in premature infants. This article is protected by copyright. All rights reserved.
Après un rappel des travaux démontrant l'activité anticomplémentaire des globulines γG agrégées par chauffage, les méthodes actuelles de mesure de cette activité soni exposées. Il résulte des travaux de nombreux auteurs que la globuline γG 7S serait dépourvue d'activité anticomplémentaire, alors que les formes polymérisées de globuline γG (9–10 S; 20–40 S) seraient douées d'activité anticomplémentaire (aussi bien in vitro qu'in vivo) en raison d'une dimérisation du fragment Fc. L'inactivation du complément par la globuline γG polymérisée se produit selon un mécanisme identique à celui de la fixation du complément par un immun-complexe.
Les résutats d'une étude effectuée sur des protéines isolées au Centre National de Transfusion Sanguine sont rapportés : aucune activité anti-complémentaire n'a été décelée, même après chauffage à 56° C ou 63° C, sur les protéines suivantes : transferrine, haptoglobine, orosomucoïde, globuline β1C, globuline γA, globuline γM (de maladie de Waldenström) α-, γ- et β-lipoprotéines (conservées à 4° C). Certaines préparations de céruloplasmine présentent une activité anticomplémentaire.
Des préparations de γ-globulines injectables par voie intraveineuse cnt été obtenues au Centre National de Transfusion Sanguine sans altération de la structure moléculaire. Dépourvues d'activité anticomplémentaire in vitro et in vivo (chez l'animal normal et l'homme normal), elles sont bien tolérées par les sujets hypogammaglobulinémiques.
Le mode de préparation de la globuline γG peut influer sur l'apparition d'une activité anticomplémentaire. Le tracé d'ultracentrifugation ne concordant pas toujours avec l'existence d'une activité anticomplémentaire, l'induction d'une activité anticomplémentaire pourrait relever d'un phénomène plus subtil que la simple agrégation moléculaire.
ResearchGate has not been able to resolve any references for this publication.