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At least 865 records · Page 48Linked to original sources
PubMed1993

Killing of Trichomonas vaginalis by complement-mediated lysis is not associated with the presence of Trichomonas vaginalis virus.

We have examined the possible relationship between trichomonad killing by human serum and the presence of virus-encoded double-stranded ribonucleic acid in T. vaginalis (TVV). Indirect immunofluorescence assay revealed that non-immune serum (NIS) and T. vaginalis-immune serum (TVIS) had immunoglobulin G (IgG) antibody titres of 1:8 and 1:256, respectively, against T. vaginalis. Among the 12 isolates of T. vaginalis examined, 9 were infected with TVV. Upon long-term (> 9 months) culture, of the 9 infected isolates, 3 isolates lost the virus during the passage process. Five of 9 TVV-infected isolates were completely killed by 10% NIS while the other 4 TVV-infected isolates had viability over the range 22-81%. Three fresh non-TVV-infected isolates had viability over the range 12-89%. On the other hand, no trichomonads survived in the presence of 10% TVIS. Viability of the virus-lost isolates during long-term culture was not altered when compared with that of their corresponding fresh isolates. Heat-inactivated-NIS and -TVIS had no killing effect on trichomonads while absorbed-NIS and -TVIS (ATVIS) had a similar killing effect to NIS. Further studies on the role of antibody and complement in the killing of trichomonads by serum revealed no significant difference in trichomonad viability between treatments of Mg2+-ethylene glycol-bis-(beta-aminoethyl ether)- N,N,N1,N1- tetraacetic acid (Mg(2+)-EGTA)-TVIS and of Mg(2+)-EGTA-ATVIS. Zymosan-treated ATVIS did not kill trichomonads but zymosan-treated TVIS had a marked killing effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Microassay for colorimetric estimation of complement activity in guinea pig, human and mouse serum.

A sensitive colorimetric microassay for determining haemolytic complement activity was devised. It is carried out in U-welled microtitre dishes covered with plastic tape, which are incubated in a waterbath and subsequently centrifuged. The supernatant is transferred to flat-bottomed microtitre dishes and haemolysis is estimated by automatic measuring of the absorption using an interference filter of 405 nm in a Titertek Multiskan. Advantages of the method described are saving time and materials, and avoiding the use of radioactive nuclides. This microassay may therefore be a useful substitute for macro and semi-micro tests for colorimetric determination of serum complement activity and for microassays based on the release of a radio-isotope.

Animals↗
PubMed1985

A simplified method for the preparation of EAC14 intermediate cells using human serum treated with methylprednisolone.

The inhibitory effect of methylprednisolone 21-succinate ester (MPS) on the activities of complement components in human serum was studied by incubating human serum with various concentrations of MPS at 37 degrees C for 30 min and then measuring the residual activity of each component in human serum. The formation of EAC1 and EAC14 by C1 and C4 respectively, were only weakly inhibited by MPS at a final concentration of 10 mg/ml. In contrast, the same concentration of MPS completely inhibited the capacity of C2, C3, C5 and C6-9 to induce respective succeeding intermediates. On the basis of these findings a simplified method was devised for the preparation of EAC14 intermediates using human serum pretreated with MPS.

Animals↗
PubMed1986

Rapid recovery of non-hemolyzed serum and untraumatized cells by using a new method of blood defibrination in vitro.

Platelet-free cellular elements and non-hemolyzed, chemically unaltered serum are important research components of the cellular immunology laboratory. Both can be recovered from the same peripheral blood sample if it is properly defibrinated. The numbers of cells recovered from heparinized aliquots of blood from healthy donors were not significantly different from the numbers of mononuclear leukocytes, polymorphonuclear leukocytes, and erythrocytes recovered from blood samples which had been mechanically defibrinated in vitro with a stationary, cone-shaped 'TP'-like device which we here describe. Compared with serums obtained from clotted blood, or from blood defibrinated by using glass beads, we found that serums from blood defibrinated with the 'TP'-like device had the lowest detectable levels of hemoglobin, free DNA, or LDH. Serums from TP-defibrinated blood were not different from clotted serum samples with regard to the function of the classical complement pathway, the alternative complement pathway, C4 hemolytic activity, and most serum chemistries. Use of the TP-defibrinator in immunology laboratories is an ideal way to prepare blood for rapid isolation of cellular elements and non-hemolyzed serum from the same sample.

Aspartate Aminotransferases↗
PubMed1990

Quantitation of C4 nephritic factor by an enzyme-linked immunosorbent assay.

We have developed an enzyme-linked immunosorbent assay (ELISA) for the quantitation of C4 nephritic factor (C4NeF). Incubation of the C4NeF-positive serum from patient M.I. with normal human serum (NHS) in the presence of human aggregated IgG (AHG) resulted in the formation of stable C4-C2 complex. No complex was formed in EDTA or under the condition free of AHG. The reaction mixture was filtered through an ACA 22 column, from which the C4-C2 complex was eluted at the first protein peak. When IgG purified from M.I. serum was incubated with NHS and AHG, C4-C2 complex also increased in proportion to dose of the purified M.I. IgG. These results show that C4NeF in M.I. serum stabilizes C4b2a convertase of the classical complement pathway, and is quantified by the ELISA. C4NeF activity was measured, using the ELISA method, in patients with various glomerular diseases, and found elevated in three of 24 patients with membranoproliferative glomerulonephritis (MPGN) type I and slightly but distinctly positive in seven of 24. No C4NeF was detected in two C3 nephritic factor-positive patients with MPGN type II and six with active systemic lupus erythematosus. The new method was more simple and quantitative than C4b2a stabilization assay for C4NeF.

Animals↗
PubMed1994

Homogeneous immunoassay of antibody by use of liposomes made of a model lipid of archaebacteria.

Liposomes made of 1,2-di(3RS,7R,11R-phytanyl)-sn-glycero-3-phosphocholine (DPhyPC), which was synthesized as one of the model lipids existing in archaebacterial halophiles, showed excellent stability. Because of this high stability, DPhyPC liposomes could be constituted high ratios (50%) of N-[4-(p-maleimidophenyl) butyryl] dipalmitoyl phosphatidylethanolamine (MPB-DPPE), and consequently could bind large amounts of antigen (alpha-chymotrypsinogen A) on the liposome surface in comparison with those made of ordinary lipids, such as dipalmitoylphosphatidylcholine (DPPC). Though the characteristics of the DPhyPC liposomal membranes in lysis by the classical complement pathway were similar to those of DPPC liposomes, a high sensitivity and a low detection limit in the liposome immune lysis assay (LILA) of antibodies were attained by binding large amounts of the antigen. Further, by coupling sufficient amounts of antigen, almost all the DPhyPC liposome surface was covered with the antigen, and such liposomes showed higher resistance against non-specific lysis caused by complement activity in serum samples, which may be effective in reducing positive-false errors in LILA.

Animals↗
PubMed1990

Complement activation in pulmonary tuberculosis.

The alterations in serum/plasma levels of total haemolytic complement activity (CH50), complement components C3 and C3d, and circulating immune complexes (CICs) in patients with pulmonary tuberculosis were analysed in relation to the severity of disease and treatment status. The mean levels of CH50, C3, C3d and CICs were significantly higher in untreated than treated patients and in normal controls. In the untreated group, the level of each of these four parameters except C3d was significantly higher in patients with far advanced disease than in those with moderately advanced disease, whereas the difference between treated patients and normal controls was not statistically significant for any of the four parameters tested. There were statistically significant correlations between levels of CICs and both C3 and C3d in the untreated tuberculosis patients. However, the correlations for the same parameters were not significant when treated patients were considered. The CH50 levels in tuberculosis patients suggest a functional classical complement pathway, which is essential for immune complex solubilisation. High C3d level in untreated patients is indicative of increased complement activation, which in turn shows significant correlation with levels of CICs. It appears that the intact and elevated complement proteins and their proper activation by CICs prevents tuberculosis from becoming a typical immune complex disease.

Adult↗
PubMed1990

Properties of four acute phase proteins: C-reactive protein, serum amyloid A protein, alpha 1-acid glycoprotein, and fibrinogen.

Four plasma proteins, referred to as positive acute phase proteins because of increases in concentration following inflammatory stimuli, are reviewed: C-reactive protein (CRP), serum amyloid A protein (SAA), alpha 1-acid glycoprotein (AAG), and fibrinogen. The CRP and SAA may increase in concentration as much as 1000-fold, the AAG and fibrinogen approximately twofold to fourfold. All are synthesized mainly in the liver, but each may be produced in a number of extrahepatic sites. The role of cytokines in induction of the acute phase proteins is discussed, particularly the multiple functional capabilities of interleukin-6 (IL-6). Other cytokines that regulate acute phase gene expression and protein synthesis include IL-1, tumor necrosis factor alpha, interferon gamma, as well as other stimulatory factors and cofactors. The physicochemical characteristics of each protein are reviewed together with the molecular biology. For each protein, the known biological effects are detailed. The following functions for CRP have been described: reaction with cell surface receptors resulting in opsonization, enhanced phagocytosis, and passive protection; activation of the classical complement pathway; scavenger for chromatin fragments; inhibition of growth and/or metastases of tumor cells; modulation of polymorphonuclear function; and a few additional diverse activities. The role of plasma SAA is described as a precursor of protein AA in secondary amyloidosis; other functions are speculative. AAG may play an immunoregulatory role as well as a role in binding a number of diverse drugs. In addition to clot formation, new data are described for binding of fibrinogen and fibrin to complement receptor type 3. Finally, the concentration of each protein is discussed in a wide variety of noninfectious and infectious disease states, particularly in connective tissue diseases. The quantification of the proteins during the course of various acute and chronic inflammatory disorders is useful in diagnosis, therapy, and in some cases, prognosis.

Acute-Phase Proteins↗
PubMed1990

Extensive C1q-complement initiated lysis of human platelets by IgG subclass murine monoclonal antibodies to the CD9 antigen.

Several monoclonal antibodies (MAbs) to CD9, a surface membrane glycoprotein of 24 kDa found on platelets as well as several other hematopoietic and nonhematopoietic tissues, have the property of activating platelets. We have recently shown that with two of these MAbs (ALB-6 and SYB-1) this activation is mediated by interaction of the Fc portion of these IgG1 subclass MAbs with the Fc gamma II receptor (FcRII) and is blocked by a MAb to this receptor (IV-3). In this report we show that several MAbs to the CD9 antigen (BA-2, BU-16, MM2/57) also cause extensive and rapid platelet lysis in plasma. This lysis is mediated by the classical complement pathway dependent on C1q fixation. Lysis was not blocked by inhibiting platelet activation with prostaglandin E1 or by the MAb to FcRII (IV-3). The CD9 MAb BU-16 can also activate platelets through the FcRII when complement lysis is prevented by removal of C1q using specific antisera or by isolation of the platelets from plasma.

Animals↗
PubMed1986

Interaction between immune complexes and C3b receptors on erythrocytes.

We studied the interaction between immune complexes (IC) and C3b receptors (CR1) on erythrocytes (E) and showed that activation of the classical complement pathway is essential for the binding of IC to CR1, that C3b inactivator (I) and beta 1H (H) are essential for the release of IC from CR1, that CR1 retain the capacity to bind IC after repeated binding and release of IC, and that on the other hand, IC lose the capacity to bind to CR1 after repeated binding and release. These results suggest a dynamic in vivo interaction between IC and CR1 on E which are supposed to transport IC to the reticuloendothelial system. CR1 on E, with a help of I and H, might make IC less harmful to the tissues in the process of releasing IC from E.

Antigen-Antibody Complex↗
PubMed1977

Quantitative requirements for C3 to induce Forssman systemic shock and cutaneous hemorrhagic vasculitis in guinea pigs.

The requirements of complement (C) to induce systemic and cutaneous Forssman reactions were studied in inbred DHC-BA and Hartley strain guinea pigs. After intravenous injection of Forssman antibody, fatal systemic shock was associated with a marked drop in CH50, C4, and C3 and a lesser decrease in C5 hemolytic activity. Platelet counts and leukocyte counts dropped as well. With the use of the purified low molecular weight factor from cobra venom (CVF) to deplete C3, guinea pigs with less than 1% intravascular C3 were protected from lethal shock. Approximately 1% to 3% C3 activity is required for Forssman cutaneous vasculitis. These results confirm earlier studies that classical complement pathway activation occurs in Forssman shock and demonstrate the exquisite biologic efficiency of C3 in provoking the shock syndrome.

Anaphylatoxins↗
PubMed1983

Kinin formation in hereditary angioedema plasma: evidence against kinin derivation from C2 and in support of "spontaneous" formation of bradykinin.

Hereditary angioedema (HAE) is due to a functional deficiency of the inhibitor of the activated first component of complement (C1 INH). This abnormality is thought to be responsible for the generation of a kininlike peptide in HAE plasma that is derived from the second component of complement (C2). Specifically, a combination of C2 cleavage by C1s and C2 fragment cleavage by plasmin has been reported to generate a kinin that is distinguishable from bradykinin. We have attempted to generate this peptide by activating the classical complement pathway by incubation of plasma with immune complexes and then adding plasmin or by incubating purified C1s with C4 and C2 and then adding either plasmin or trypsin. We performed a total of 13 experiments, and in no case was a kininlike molecule generated as assessed by contraction of the estrus rat uterus. However, incubation of EDTA-treated HAE plasma at 37 degrees C for time intervals up to 1 hr progressively generated a smooth muscle-contracting activity. This activity was resistant to tryptic digestion but was destroyed after incubation with carboxypeptidase B, an inhibition profile consistent with that of bradykinin. We therefore propose that bradykinin alone, or in combination with other factors heretofore unrecognized, might be responsible for the swelling that is characteristic of hereditary angioedema.

Angioedema↗
PubMed1985

Angioimmunoblastic lymphadenopathy in a child with unusual clinical and immunologic features.

We report a case of angioimmunoblastic lymphadenopathy in a child followed for 13 years. Unusual features include prolonged course, cold urticaria, nonthrombocytopenic purpura, poor wound healing, transfusion reactions, and possible neurologic involvement with cerebritis and epileptic seizures. The patient's serum contained a monoclonal cryoglobulin, immunoglobulin G, kappa light chain type, that activated the classic complement pathway in vitro and mediated passive transfer of the cold urticaria. The patient responded well to corticosteroids and has been in clinical remission for 8 years without specific treatment. There is immunologic evidence of persistent residual disease activity. This case illustrates the remarkable diversity of clinical and immunologic features and the variable prognosis of this disorder.

Adolescent↗
PubMed1984

Restriction of C1 hemolytic function by human proline-rich salivary proteins.

Acidic proline-rich salivary proteins, PRPI, PRPII, PRPIII, PRPIV, upper Db and Statherin, were isolated from parotid saliva and tested for interaction with complement. It was determined that each of the isolated proline-rich proteins blocked C1 hemolytic activity in assay systems where C1 was rate-limiting. Further studies comparing the specific activity of the proline-rich proteins to unfractionated parotid saliva indicated that other salivary substances (sensitive to urea treatment of parotid saliva) were also interacting with the first complement component but in a time-dependent manner. Based on a series of experiments examining the effect of the sequence of addition of the proline-rich proteins in the complement assay systems, it is postulated that these salivary proteins are able to block the proper interaction of C1 with EAC4 cells (sheep erythrocytes coated with antibody and C4gp). The proline-rich salivary proteins had no effect on C1 once C1 was bound to the immune complexes on the EAC4 cells. The C1 macromolecular complex undergoes conformational changes upon interaction with immune complexes resulting in a more avid binding of the C1q-Clr-Cls subunits with one another. Thus it is speculated that the EAC4-bound C1 becomes resistant to disruption by the proline-rich salivary proteins. Although the urea-sensitive factors had the highest specific C1-fixing activity, the activity of the acidic proline-rich proteins on C1 is important because of their relatively high concern in salivary secretions. Since complement-containing serous exudates and transudates are present on inflamed mucosal tissues, salivary substances which interact with C1 may play a role in regulating the initiation of the classical complement pathway, particularly at those mucosal sites where there is a high ratio of salivary secretion to serous exudate.

Chromatography, Gel↗