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PubMed1980

Basophil "releasability" in patients with asthma.

This study was based on the premise that mediator release plays a role in the pathogenesis of allergen-induced as well as nonallergen-induced asthma. We studied histamine release from human basophils obtained from patients with asthma and from control subjects. These cells were challenged with several different stimuli: goat anti-human IgE-Fc, C5-peptide, N-formyl-methionyl-leucyl-phenylalanine (f-met peptide), Ca++ ionophore A23187, hyperosmolar mannitol, and D2O. Release induced by any one stimulus was unrelated to the response to any other stimulus. The basophils of patients with asthma and control subjects responded similarly to most stimuli: they were significantly less responsive to C5-peptide and f-met peptide, and significantly more responsive to D2O. The results suggest that there is a parameter of releasibility that must be defined for each separate stimulus, and that patients with asthma can be differentiated from normal persons by the response of their basophils to selected stimuli.

Adult↗
PubMed1985

The acute phase response of C3, C5, ceruloplasmin, and C-reactive protein induced by turpentine pleurisy in the rabbit.

Concentrations of five serum proteins, C3, C5, ceruloplasmin, C-reactive protein, and albumin, have been measured during the acute phase response in rabbits with turpentine-induced pleurisy. C-reactive protein concentrations in the circulation rose abruptly between 12 and 36 hours to a level greater than 50 times the pretreatment concentration, then returned to undetectable amounts by 96 hours. C3 and ceruloplasmin both showed some increase in concentration by 12 hours and reached their maximum concentrations of two to three times the baseline levels 48-72 hours after the turpentine treatment. Concentrations were still elevated at 120 hours, after which time they gradually returned to normal. C5 and albumin concentrations in the turpentine-treated rabbits did not differ from the baseline concentrations. The same five proteins were measured in the inflammatory exudate. C-reactive protein was not detectable at any of the time points. C3, C5, ceruloplasmin, and albumin were present in normal pleural fluid at roughly half their serum concentrations. The activities of C3, C5, and ceruloplasmin were low in the early exudate, but C3 and C5 activity rose relative to their concentrations in the later samples of pleural fluid. The specific activities of C3 and C5 were higher in the pleural fluid at 72 hours than in plasma, while that of ceruloplasmin remained less in the pleural fluid than in plasma throughout the experiment. The involvement of these proteins and their relation to the inflammatory response are discussed.

Acute-Phase Proteins↗
PubMed1978

Studies on immunosuppression by cobra venom factor. III. On early responses to sheep erythrocytes in C5-deficient mice.

CVF administered before immunization can profoundly depress humoral responses in C-sufficient mice. In AKR/JC5- mice given CVF before i.v. immunization with SRBC, only IgG levels were depressed, IgM titers being equivalent to those of untreated controls. The immunosuppressive effect became inapparent when the i.p. route of immunization was adopted. In DBA/2J C5- mice reduction of both IgG and IgM titers was observed irrespective of the route of immunization. The degree of suppression was, however, much more marked when mice were challenged intravenously. Essentially identical results were obtained with C5+ DBA/1J mice. These studies indicate that immunosuppression by CVF is unrelated to activation of the late C components. The significance of these findings is discussed with reference to the possibility that the generation of biologically active C fragments in conjunction with a C3 deficiency may account for immunosuppression by CVF.

Animals↗
PubMed1986

Superoxide generation by synovial fluid neutrophils enhanced by immune complexes and suppressed by rheumatoid factor in synovial fluid.

Synovial fluid (SF) from patients with rheumatoid arthritis (RA) enhanced superoxide generation by neutrophils isolated from RA SF, in contrast to SF from patients with osteoarthritis. These superoxide generation-enhancing substances may be intermediate-sized immune complexes and a complement C5-derived fragment. Rheumatoid factor (RF) isolated from RA SF suppressed superoxide generation-enhancing activity of aggregated IgG. Therefore, biologically active RF may block the interaction of the immune complexes with neutrophils accumulating in RA SF, and protect the joint tissue from the effects of oxygen radicals or proteases.

Antigen-Antibody Complex↗
PubMed1992

Neutrophil chemotactic factors in the respiratory tract of patients with chronic airway diseases or idiopathic pulmonary fibrosis.

This study was designed to clarify the contributions of specific neutrophil chemotactic factors (NCF) in neutrophil accumulation in the human respiratory tract associated with various diseases. The activity and characteristics of the NCF in the bronchoalveolar lavage (BAL) fluid and culture media of alveolar macrophages obtained from normal volunteers, control patients, patients with chronic airway diseases (CAD) and patients with idiopathic pulmonary fibrosis (IPF) were examined. The BAL fluid from normal volunteers contained NCF comparable with the chemotactic factors interleukin-8 (IL-8) and leukotriene B4 (LTB4). Analysis of the biochemical characteristics of NCF released from alveolar macrophages suggests that they are derived from alveolar macrophages. The NCF activities in BAL fluids from patients with CAD and IPF were higher than those in BAL fluids from normal volunteers and control patients. Biochemical analysis demonstrated that several kinds of NCF, including those derived from the complement component C5 and alveolar macrophages, were present in the BAL fluid from patients with CAD and respiratory infections. The especially marked increase of C5-derived NCF indicate their importance in neutrophil accumulation in the respiratory tract of patients with CAD. Alveolar macrophages released different types of NCF after different lengths of culture periods (4 h and 24 h). Alveolar macrophages from patients with IPF released larger amounts of NCF than alveolar macrophages from normal volunteers, indicating the importance of alveolar-macrophage-derived NCF as well as C5-derived NCF in neutrophil accumulation in the respiratory tract of patients with IPF. These results suggest that various types of NCF increase in response to different disease states of the respiratory tract and serve to regulate the accumulation of neutrophils.

Adult↗
PubMed1985

IgG-mediated viral clearance in experimental infection with herpes simplex virus type 1: role for neutralization and Fc-dependent functions but not C' cytolysis and C5 chemotaxis.

For determination of whether the Fc moiety is required for antibody effectiveness in models of herpes simplex virus type 1 (HSV-1) infection, the effects of immune IgG and F(ab')2 fragments were compared by using a passive transfer model of footpad infection. In the IgG- and the F(ab')2-treated groups illness developed in 2 (10%) of 20 and 6 (25%) of 24 mice, respectively, compared with 10 (63%) of 16 controls. IgG treatment markedly, and F(ab')2 treatment moderately, reduced footpad viral titer and viral spread to sciatic nerve and spinal cord. The marked viral clearance by IgG was not attributable to C'-dependent lysis because rapid viral clearance was observed in C5-deficient B10.D2/oSn mice. Viral latency as a consequence of acute infection occurred in 38 (63%) of 60 lumbosacral dorsal root ganglia in the control group, 5 (8%; P less than .001) of 60 in the IgG-treated group, and 26 (33%; P less than .01) of 78 in the F(ab')2-treated group.

Animals↗
PubMed1981

Role of complement in porphyrin-induced photosensitivity.

Addition of porphyrins to sera of guinea pigs in vitro, followed by irradiation with 405 nm light, resulted in dose-dependent inhibitions of hemolytic activity of complement (CH50, C3, and C5). With guinea pig as an animal model, we also found that systemically administered porphyrins, followed by irradiation with 405 nm light, resulted in dose-dependent inhibition of CH50 in vivo. The erythrocytes from porphyrin-treated guinea pigs showed an increased susceptibility to hemolysis induced by 405 nm irradiation in vitro. Clinical changes in these animals were limited to light-exposed areas and consisted of erythema, crusting, and delayed growth of hair. Histologically, dermal edema, dilation of blood vessels, and infiltration of mononuclear and polymorphonuclear cells were observed. Guinea pigs irradiated with ultraviolet-B developed erythema, but had no alteration of their complement profiles. It is suggested that complement products may play a specific role in the pathogenesis of the cutaneous lesions of some porphyrias.

Animals↗
PubMed1992

Effects of K-76COOH (MX-1) on immune response: induction of suppressor T-cells by MX-1.

K-76COOH (MX-1), isolated from the cultured supernatant of a species of fungi imperfecti, Stachybotrys complement nov. sp. K-76, is an inhibitor of the complement component, C5. The effects of MX-1 on various immune responses were investigated. MX-1 enhanced the response of spleen cells to PHA and LPS: MX-1 at 0.01-250 micrograms/ml for PHA and at 10-250 micrograms/ml for LPS. In contrast, it inhibited the response to Con A: MX-1 at 0.01-500 micrograms/ml for spleen cells and at 100-500 micrograms/ml for thymocytes. MX-1 and IL-1 synergistically acted to enhance the Con A response of spleen and thymus cells from which accessory cells and Ia-positive cells had been removed by passing through Sephadex G-10 columns and treating with anti-Ia monoclonal antibody plus complement. T-cells pretreated with MX-1, IL-1 and Con A for 3 days suppressed not only the response of B-cells to LPS but also the production of anti-SRBC antibodies. In addition, MX-1 was found to increase CD8+ T-cells. These results suggest that MX-1 acts on T-cells to induce suppressor T-cells.

Animals↗
PubMed1986

Modulation of the immune response by anaphylatoxins.

Bioactive C3a and C5a fragments derived from the human complement compounds C3 and C5, respectively, possess immunoregulatory activities. C3a and C5a differentially influence in vitro immune function. C3a was found to be a potent suppressor of antigen-specific and polyclonal antibody responses. In contrast, C3a was unable to suppress antigen-or mitogen-induced B and T cell proliferation. Analyses of synthetic peptides based on the sequences of C3a revealed that the carboxy-terminal region of the molecule is responsible for immunosuppression. C3a-mediated suppression occurs through the activation of a nonspecific suppressor T cell pathway. In contrast to the results obtained with C3a, C5a was found to augment both in vitro humoral and cell-mediated immune responses. Regulation of immune function by complement components may form part of an in vitro nonspecific immunoregulatory network.

Adjuvants, Immunologic↗
PubMed1992

Mechanism of resistance to complement-mediated killing of bacteria encoded by the Salmonella typhimurium virulence plasmid gene rck.

We find that pADEO16, a recombinant cosmid carrying the rck gene of the Salmonella typhimurium virulence plasmid, when cloned into either rough or smooth Escherichia coli and Salmonella strains, confers high level resistance to the bactericidal activity of pooled normal human serum. The rck gene encodes a 17-kD outer membrane protein that is homologous to a family of virulence-associated outer membrane proteins, including pagC and Ail. Complement depletion, C3 and C5 binding, and membrane-bound C3 cleavage products are similar in strains with and without rck. Although a large difference in C9 binding was not seen, trypsin cleaved 55.7% of bound 125I-C9 counts from rough S. typhimurium with pADEO16, whereas only 26.4% were released from S. typhimurium with K2011, containing a mutation in rck. The majority of C9 extracted from rck strain membranes sediments at a lower molecular weight than in strains without rck, suggesting less C9 polymerization. Furthermore, SDS-PAGE analysis of gradient peak fractions indicated that the slower sedimenting C9-containing complexes in rck strains did not contain polymerized C9 typical of the tubular membrane attack complex. These results indicate that complement resistance mediated by Rck is associated with a failure to form fully polymerized tubular membrane attack complexes.

Antibodies, Monoclonal↗
PubMed1998

The Ii41 isoform of invariant chain mediates both positive and negative selection events in T-cell receptor transgenic mice.

The functional role of invariant chain in T-cell selection events and antigen presentation is well established. The invariant chain gene encodes differentially spliced isoforms, Ii31 and Ii41. The Ii41 isoform has been described to increase the efficiency of antigen presentation. We have analysed the effect of the Ii41 isoform on positive and negative selection of transgenic CD4 T cells with specificity for a natural self antigen (C5) which are crucially dependent on invariant chain for their development and functional antigen recognition. The data show that Ii41 fully substitutes for wild-type invariant chain in both positive and negative selection events during functional maturation of T cells with specificity for a natural, blood-borne self antigen.

Animals↗
PubMed1974

Hypocomplementemic and normocomplementemic acute nephritis in children: a comparison with respect to etiology, clinical manifestations, and glomerular morphology.

Of 182 patients with acute glomerulonephritis, 20 had normal C3 levels at onset. Normocomplementemic and hypocomplementemic patients were similar with respect to incidence and site of preceding streptococcal infection, elevation of ASO titer, distribution by age, sex, race, season, and year,\and glomerular morphology by light and electron microscopy. They differed in that the normocomplementemic patients tended to have normal serum C5 levels and, for reasons not clear, reduced serum albumin and elevated cholesterol levels. The consistent absence by immunofluorescence of IgG in the glomeruli of five hypocomplementemic patients and its presence in five normocomplementemic patients was considered a chance observation. The data suggest that in each group the nephritis was poststreptococcal and that the mechanism producing poststreptococcal glomerulonephritis is capable of acting independently of that activating circulating C3.

Acute Disease↗
PubMed1984

Genetic control of resistance to Listeria monocytogenes: regulation of leukocyte inflammatory responses by the Hc locus.

The control mechanisms responsible for the innate resistance of C57BL/6J (B) mice and for the innate susceptibility of A/J (A) mice to infection with Listeria monocytogenes were studied by typing the recombinant inbred (RI) strains derived from these two progenitors for the trait of Listeria resistance/susceptibility. The strain distribution pattern (SDP) of this trait obtained in the 13 AXB/BXA RI strains studied suggests that an allelic difference at a major locus (Lr-1) is responsible for the trait of resistance/susceptibility to Listeria. In addition, another putative gene (Lr-2) unlinked to Lr-1 is postulated to control the level of bacterial load within the group of susceptible strains. The SDP of A and B alleles at the Lr-1 locus was fully concordant with that observed for the Hc locus (controlling the level of the C5 component of complement). This suggests that the genetic susceptibility of A strains of mice to Listeria infection is either directly due to or related to the C5 deficiency found in that strain. This conclusion is enhanced by the observation of a significant protection of A mice from listeriosis by the infusion of C5-rich serum. A survey of RI strains for the magnitude of PMN and macrophage inflammatory responses showed that the expression of both traits co-segregated and that the C5 deficiency was the major factor responsible for the defective inflammatory response of A strain mice. We conclude that a defect in the phagocyte inflammatory responses caused by C5 deficiency is the major reason for the extreme susceptibility of A mice to Listeria.

Animals↗
PubMed2004

Excessive porcine circovirus type 2 antibody titres may trigger the development of porcine dermatitis and nephropathy syndrome: a case-control study.

In a case-control study, the role of porcine circovirus 2 (PCV2) and putative co-factors in the development of porcine dermatitis and nephropathy syndrome (PDNS) were investigated. Pigs with and without PDNS were examined for macroscopic lesions and histopathology. In addition, organs and tissues were collected at necropsy and examined for the presence of fibrinous deposits (immune complexes), CD8+ cells, and for the presence of bacterial and viral infections. Results from PDNS cases were compared with those of three control groups comprising pigs without clinical signs of PDNS and selected from; (1) the same compartment as PDNS cases, (2) another compartment but in the same PDNS herd, and (3) a control herd without any history of PDNS or post-weaning multisystemic wasting syndrome. Macroscopic and histopathological lesions found in PDNS cases were comparable to those previously documented for PDNS e.g. skin lesions and renal lesions representing glomerulonephritis associated with fibrinous deposits and to a lesser extent with interstitial nephritis. PCV2 was detected by PCR in 100% of the PDNS cases, mainly in lymph nodes and tonsils, and in 63% of the control pigs from PDNS free herds. Virus isolation did not reveal infectious PCV2 in all cases. In PDNS affected pigs the PCV2 serum antibody titres were consistently extremely high and the mean PCV2 antibody titre in PDNS pigs was significantly higher than the mean PCV2 antibody titres in pigs from all 3 control groups. Immunohistochemical investigation of kidneys from PDNS affected pigs revealed an increased accumulation of IgG1 + IgG2 and IgM, the complement factors C1q and C3, but also an increase of CD8+ cells. The amounts of IgA and the complement factor C5 in kidneys of PDNS pigs were only slightly increased as compared to control pigs. This study demonstrates that PCV2 infections can result in extremely high PCV2 antibody titres and that PCV2 is a candidate as primary agent in the development of PDNS. The causative physiological basis for PDNS may be the excessive levels of PCV2 antibodies.

Animals↗
PubMed2000

[A novel monocyte chemotactic factor that connects innate immunity and acquired immunity].

A monocyte chemotactic factor was separated from rheumatoid arthritis synovium, and identified as a homo-dimer of S19 ribosomal protein. When S19 protein was treated with the plasma transglutaminase, an inter-molecular isopeptide bond was formed between Lys122 and Gln137, and the chemotactic activity appeared. The S19 protein dimer caused chemotaxis via the receptor on monocytes to C5a, the complement C5-derived chemotactic factor. This dimer antagonized the C5a receptor on neutrophils. This dimer was released from apoptotic cells, and functioned in the phagocytic clearance of these cells by recruiting circulating monocytes. After engulfment, the macrophages moved to regional lymph nodes, and presented apoptotic cell-derived antigens to T cells. T cells proliferated and activated B cells, and eventually the IgM antibody response was observed. Cooperation between the innate immune response and the acquired response would induce an effective host defense primarily against viral infection.

Animals↗
PubMed1985

Carbohydrate composition of the second, third and fifth components and factors B and D of human complement.

The carbohydrate composition of the second, third and fifth components of human complement (C2, C3 and C5) and of factors B and D was determined employing gas-chromatographic and mass-spectrometric methods. C2 was found to contain 15.9% carbohydrate composed of fucose, galactose, mannose, N-acetylglucosamine and N-acetylneuraminate (approximate molar ratio 1:4:9:9:4). N-acetylglucosamine and mannose (approximate molar ratio 1:4), amounting to 1.7% of the mass of the molecule, were the only monosaccharides detected in C3. C5 contained 3.8% carbohydrate composed of galactose, mannose, N-acetylglucosamine and N-acetylneuraminate (approximate molar ratio 2:4:4-5:2). The carbohydrate moiety of B consisted of fucose, galactose, mannose, N-acetylglucosamine and N-acetylneuraminate (molar ratio 1:2:3:4:2). The total carbohydrate content of B was estimated at 8.6%. In addition to these monosaccharides, glucose (0.4-0.9%) was also detected in all preparations analysed. Glucose was the only sugar detected in D.

Carbohydrates↗
PubMed1986

A simplified method for purification of human C5a from citrated plasma.

A simplified immunoadsorption technique has been developed to purify human C5a. the 11 000 Da glycopeptide produced by C5 convertase cleavage of the fifth component of complement. In this method, human C5 fragments, including C5a, are isolated from zymosan-activated plasma by affinity chromatography, concentrated on CM 52 cellulose, and then purified to homogeneity by gel filtration on Sephadex G-75 in phosphate-buffered saline. Human C5a prepared by this technique demonstrates characteristic immunochemical and biological activity. This method has also been adapted for the purification of 125I-C5a in phosphate-buffered saline. This technique offers a simplified approach to the purification of this important soluble mediator of inflammation.

Biological Assay↗
PubMed1988

Complement factors in fetal and maternal blood and amniotic fluid during the second trimester of normal pregnancy.

Complement factors (C3, C4, C5; Factors B, H and I) were measured in maternal and fetal serum and amniotic fluid obtained from 55 women with singleton pregnancy undergoing diagnostic fetoscopy at 15 to 28 weeks gestation. Maternal serum levels were consistently 10 times higher than fetal levels which in turn were 10 times higher than levels in amniotic fluid. Spearman rank correlation analysis at weeks 20 to 22 (n = 20) revealed a statistically significant correlation between maternal and fetal levels of C3 and Factors B and I, and between maternal and amniotic fluid levels of Factors B and I. A significant increase in fetal levels of C3, C4 and Factor H, and in amniotic fluid levels of C3 and Factor B was seen in relation to advancing gestational age. These differences were not seen in maternal serum during the short interval of pregnancy studied. These data confirm earlier assumptions of fetal synthesis of complement factors, and provide normal reference ranges of complement factors in fetal blood and amniotic fluid.

Amniotic Fluid↗