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PubMed1977

Analysis of established human carcinoma cell lines for lymphoreticular-associated membrane receptors.

Thirty-one different long-term established human carcinoma culture cell lines were examined for the presence or absence of receptors for the Fc portion of immunoglobulin G (IgG) ("Fc receptors"), the third component of complement (C3 receptors), sheep erythrocytes and mouse erythrocytes. Included in the catalogue of lines tested were adenocarcinoma of the adrenal cortex, colon, rectum, lung, liver, breast and kidney, and carcinomas of the uterine cervix, bladder and vulva. All lines were found to be consistently Fc receptor-negative, as assayed by rosette formation with sheep erythrocytes coated with subhemagglutinating amounts of anti-sheep erythrocyte antibodies, or bovine erythrocytes heavily coated with non-hemagglutinating anti-bovine erythrocyte antibodies. This is similar to results obtained with murine tumors: carcinomas are consistently Fc receptor-negative, while those lines which are Fc receptor-positive are invariably lymphoreticular in nature. The human carcinoma cell lines were also negative for complement (C3) receptors and spontaneous T and B rosette markers. It is proposed that, in most cases, rosette-forming cells found in primary human carcinomas are, as in the mouse or rat, representative of infiltrating non-malignant lymphoreticular cells.

Adenocarcinoma↗
PubMed2005

Proteins exposed at the adult schistosome surface revealed by biotinylation.

The human blood-dwelling parasite Schistosoma mansoni can survive in the hostile host environment for decades and must therefore display effective strategies to evade the host immune responses. The surface of the adult worm is covered by a living syncytial layer, the tegument, bounded by a complex multilaminate surface. This comprises a normal plasma membrane overlain by a secreted bilayer, the membranocalyx. Recent proteomic studies have identified constituents of the tegument, but their relative locations remain to be established. We labeled the most exposed surface proteins using two impermeant biotinylation reagents that differed only in length. We anticipated that the two reagents would display distinct powers of penetration, thereby producing a differential labeling pattern. The labeled proteins were recovered by streptavidin affinity and identified by tandem mass spectrometry. A total of 28 proteins was identified, 13 labeled by a long form reagent and the same 13 plus a further 15 labeled by a short form reagent. The parasite proteins included membrane enzymes, transporters, and structural proteins. The short form reagent additionally labeled some cytosolic and cytoskeletal proteins, the latter being constituents of the intracellular spines. Only a single secreted protein was labeled, implying a location between the plasma membrane and the membranocalyx or as part of the latter. Four host proteins, three immunoglobulin heavy chains and C3c/C3dg, a fragment of complement C3, were labeled by both reagents indicating their exposed situation. The presence of the degraded complement C3 implicates inhibition of the classical pathway as a major element of the immune evasion strategy, whereas the recovery of only one truly secreted protein points to the membranocalyx acting primarily as an inert protective barrier between the immune system and the tegument plasma membrane. Collectively the labeled parasite proteins merit investigation as potential vaccine candidates.

Animals↗
PubMed1975

A receptor for the third component of complement in the human renal glomerulus.

In the course of studying the nature of mononuclear cellular infiltrates in tissue sections of human kidney it was noted that indicator sheep erythrocytes densely coated with the third component of complement (C3) specifically adhered to all of the glomeruli in the tissue sections. The deposition of complement (C) within the glomerulus is a feature of many immunologically related renal diseases (1,2), yet the precise mechanism by which C is deposited remains unexplained. We feel that this observation, suggesting the presence of a receptor for C, is, therefore, of particular interest.

Animals↗
PubMed1981

Immunologic mechanisms in the production of food sensitivities.

Fifty-five test patients and ten control patients were selected for provocation of symptoms using the oral challenge test. The provoking food was selected with the use of the leukocyte cytotoxic test. The test patients developed adverse symptomatology clinically while the control patients did not. During the phase of symptomatology it was shown that IgE did not change in the blood and, therefore, the Type I, anaphylactic type of reaction, which is IgE dependent, did not participate in symptom production. It was shown that 2 components of the classical pathway of complement C3 and C4 were utilized in the test group and not in the control group. Complement is 1 of the 2 components of the humoral system of the human immune system. C4 is one of the components that is triggered by the classic complement pathway, whose stimulus is IgG and IgM, and not by the other complement pathways. It can therefore be hypothesized that all the components of the circulatory humoral system are participating in this reaction and that Type II, the cytotoxic, and Type III, th immune-complex type of immunologic reaction, are the major contributors in the production of symptoms.

Complement Activation↗
PubMed1987

Inheritance and interaction of immune traits in beef calves.

Three sets of blood samples were obtained from beef calves of two experimental populations and assayed for various immunological measurements. The first set of samples was taken between 24 and 48 h after birth and quantified for IgG1 concentration. A second set was taken immediately prior to vaccination for infectious bovine rhinotracheitis virus (IBRV; at an average age of 164 d) and a third set taken 60 d post-vaccination. These later samples were quantified for antibodies specific to IBRV. Level of complement C3 was also quantified in the samples taken immediately prior to vaccination. Three hundred sixty-seven calves were from four Hereford lines; three lines were previously selected for growth traits and the fourth was a randomly selected control line. There were no consistent differences in immune traits among these lines. The second group of 165 animals were Angus, Hereford and Red Poll calves. While Angus calves had a higher mean IgG1 concentration at 24 to 48 h of age than Hereford or Red Poll calves, no differences among breeds were found for the other immune traits measured. Calves from older dams (greater than 3 yr old) tended to have higher mean IgG1 concentrations, pre-vaccination IBRV antibody titers and complement C3 levels than calves from 2- and 3-yr-old cows. However, these calves had lower 60-d post-vaccination IBRV titers than calves from the younger cows (P less than .05). As pre-vaccination IBRV antibody titer increased, post-vaccination IBRV antibody titer decreased (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Complete intron/exon organization of DNA encoding the alpha' chain of human C3.

The third component of human complement (C3), a central molecule in both the classical and alternative pathways of complement, is comprised of two polypeptides, termed the alpha and beta chains. Activation of C3 cleaves the alpha chain into two fragments, C3a, an inflammatory peptide, and the alpha' chain which remains covalently linked to the beta chain. Proteolytic fragments derived from the alpha' chain during activation and regulation of complement play a significant role in host defense and regulation of the immune response. Two cosmid clones covering the alpha' chain region were used to characterize the structure of this portion of the C3 gene. The alpha' chain is encoded by 24 exons, which range in size from 52 to 213 base pairs (bp) with an average size of 115 bp. The splice donor sequence at the beginning of intron 12 has a rare sequence variant of GC instead of the usual GT sequence. Ten introns have been completely sequenced and were surprisingly short, ranging in size from 85 to 242 bp with an average of 140 bp. Other introns range in size from 250 bp to over 4 kilobases in length. The gene size for this portion of C3 is estimated to be 23-24 kilobases. Comparison of exon structure with protein domains and with peptide mapping studies demonstrates that several binding sites on C3 are encoded by single exons. These data support the hypothesis that individual exons can code for functional protein domains.

Base Sequence↗
PubMed1991

Investigation of a possible correlation between rates of secretion and microsomal membrane association of plasma proteins synthesized by rat liver.

The rates of secretion of complement C3, haptoglobin and plasminogen have been determined after pulse labelling with [3H]leucine, and compared to the secretion of prothrombin, albumin and transferrin investigated previously (Kvalvaag, A.H., Tollersrud, O.K. and Helgeland, L. (1988) Biochim. Biophys. Acta 937, 319-327). To study membrane association, rough microsomes were treated with increasing concentrations of saponin, sodium deoxycholate or Triton X-100. All six proteins were quantitated in the soluble and membrane fraction by enzyme immunoassays. At concentrations of saponin from 0.08% to 0.32%, each secretory protein showed a characteristic distribution, almost identical to that obtained with 0.05% sodium deoxycholate or 0.08% Triton X-100. Albumin and transferrin with half-times for secretion (t1/2) 30 and 75 min, respectively, are both almost exclusively found in the luminal fraction (greater than 95%). Prothrombin and plasminogen, which both show an intermediate t1/2 (approx. 55 min), are partially associated with the membranes, as only about 60% was released. Haptoglobin and complement C3 also show some association with the membranes (80-85% released). C3 is secreted at the same rate as prothrombin and plasminogen (t1/2 = 55 min), whereas haptoglobin is secreted more rapidly (t1/2 = 40 min). Accordingly, no correlation between kinetics of secretion and membrane association was demonstrated.

Animals↗
PubMed1990

Studies of the acute phase response in experimental serum sickness.

The acute phase behavior of C-reactive protein (C-RP), the third component of complement (C3) and total haemolytic complement activity was studied during the course of acute serum sickness (ASS) in rabbits. The specific aim was to establish whether the induction protocol caused a significant change in the serum concentration of proteins (such as C3) which could modify the outcome of the disease. ASS was induced by an intravenous (IV) bolus of bovine serum albumin (250 mg/Kg) with or without prior subcutaneous (SC) immunization with 4 mg BSA in complete Freund's adjuvant. Thirty-six animals received a full induction regimen (i.e., both SC and IV BSA). A further six rabbits were given either IV or SC BSA alone, in order to define the basis for acute phase changes observed when both injections were given. Twelve animals received a standard acute phase stimulus with intramuscular (IM) turpentine--2 or 3 ml--as a comparison to the response observed in the experimental animals. Nine, 14 and 24 animals showed a rise in C-RP (i.e., five-fold increase), C3 and haemolytic activity (greater than 25% increase) respectively after a full induction protocol. Eight, nine and five animals showed a comparable rise with IM turpentine. Studies with IV or SC BSA alone showed that the latter was predominantly responsible for the rise in C-RP and haemolytic activity. Specifically, five and four animals respectively showed a significant rise in these two parameters. Three animals showed a rise in C-RP following IV BSA alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1987

Immunoglobulins (IgG, IgA, IgM, IgE) and complement components (C3, C4) in nephrotic syndrome due to minimal change and other forms of glomerulonephritis, a clue for steroid therapy?

Serum IgG, IgA, IgM, IgE, C3 and C4 were measured in 13 patients with minimal change (MC) glomerulonephritis and 10 with the nephrotic syndrome (NS) due to other forms of glomerulonephritis. The tests were repeated in all patients with MC glomerulonephritis when they went into remission. Serum IgG was reduced, IgM, IgE and C3 were raised while serum IgA was within the normal range when the patients were nephrotic. Changes in serum immunoglobulins and complement components were not specific to MC glomerulonephritis and these parameters reverted towards normal when the NS went into remission. Elevated C3 levels probably reflected increased hepatic protein synthesis since C3 correlated significantly with serum cholesterol. There was a tendency for serum IgE concentrations to positively correlate with the total dose of prednisolone required to bring the NS to remission.

Adolescent↗
PubMed1992

Isolation of a hagfish gene that encodes a complement component.

It has been widely accepted that cyclostomes are the most primitive vertebrates extant with the ability to produce antibodies. We isolated cDNA clones that encode a putative 'antibody' from one of the cyclostomes, Eptatretus burgeri. The amino acid sequence predicted from the nucleotide sequences of the cDNA clones indicated that this gene does actually encode the proteins isolated as hagfish 'antibodies' by various investigators. However, these proteins are not similar to mammalian immunoglobulins but have some characteristics common to complements C3, C4 and C5 in higher vertebrates. We discuss the relationships of the isolated gene for hagfish complement with the mammalian genes for complements C3, C4 and C5. We also discuss the possibility of the presence of antibodies in cyclostomes.

Amino Acid Sequence↗
PubMed1988

The surfaces of the parasitic nematodes Trichinella spiralis and Toxocara canis differ in the binding of post-C3 components of human complement by the alternative pathway.

The binding of human complement components C3, C5 and C9 to the surface of the infective larvae of the nematode parasites Toxocara canis and Trichinella spiralis, by the alternative pathway, was examined by direct and indirect immunofluorescence on the intact parasites. This showed that although C3 bound to both nematodes, they differed markedly in the binding of C5 and C9; C5 bound only minimally to T. spiralis, and C9 binding to this parasite was barely detectable. In contrast, both early and late components bound to T. canis to a high density, comparable to, or in excess of, the binding of these components to the infective larvae of the trematode Schistosoma mansoni. The lack of binding of the post-C3 components to T. spiralis did not correlate with enhanced binding of the control protein, Factor H.

Animals↗
PubMed1985

Fibronectin binds to complement-coated agarose beads and increases their association to mouse macrophages.

We have studied the binding of fibronectin to complement (C3b, C3bi, C3d)-coated agarose beads and its effect on cell association of such beads to mouse macrophages. Fibronectin bound to agarose beads preincubated in human serum, whereas no binding occurred after preincubation of the beads with complement-inactivated (50 degrees C for 20 min or ethylenediaminetetraacetic acid) sera. The binding of iodine-labelled fibronectin to beads preincubated in fibronectin-depleted serum (HS-FIB) was about twice that of beads preincubated in normal serum. Unlabelled fibronectin inhibited the following binding of labelled fibronectin to beads pretreated in HS-FIB. A similar amount of fibronectin bound to agarose beads coated with equimolar amounts of C3b, C3bi, or C3d, suggesting that the common domain C3d carries the main binding site(s) for fibronectin. Preincubation of serum-treated and trypsinized agarose beads with fibronectin led to an increased association (22%) of such beads to mouse macrophages. The results indicate that fibronectin promotes binding of complement-coated agarose beads to mouse macrophages, whereas the ingestion of the beads is mediated via complement C3 receptors.

Animals↗
PubMed1996

Increase of immunologically relevant parameters in correlation with Baker classification in breast implant recipients.

A variety of studies have suggested a possible immune reaction to silicone implants, although an increased frequency of rheumatic disorders among implant recipients could not be established. Several immunologically relevant humoral parameters were investigated in 239 breast implant recipients. The following parameters were determined: immunoglobulin G and M, complement C3 and C4, rheumatoid factor, C-reactive protein, antinuclear antibodies, antimitochondrial antibodies, and antithyroglobulin and antimicrosomal antibodies of the thyroid gland. Levels of complement C3 were elevated in 42.5% of the patients. No difference could be observed between silicone gel-filled and saline-filled implant recipients. Complement C4 was increased in 21.3% of the patients and a parallel relationship was observed between elevated C4 and C3 levels (p < 0.0015). In 28% of the patients, the antithyroglobulin titer was elevated > 200 U/ml. No difference was found between silicone gel-filled and saline-filled implant recipients. Elevation of antimicrosomal antibodies existed in 14.3% of the patients and was correlated significantly with antithyroglobulin antibodies (p < 0.0347). In accordance with the classification developed by Baker, we observed a significant correlation between capsule fibrosis types Baker I and II, and elevated C3 values (p < 0.0004) in silicone gel-filled but not in saline-filled implant recipients. Additionally, a correlation was found between increased antithyroglobulin titers (< 200 U/ml) and capsule fibrosis types Baker I and II (p < 0.0001) in this group. In the study presented here, an increase of several humoral parameters could be demonstrated in breast implant recipients, although we failed to correlate these findings with any clinical symptoms.

Adult↗
PubMed1986

Genetic markers in rheumatoid arthritis.

Genetic as well as environmental factors are believed to be of importance in the etiology of rheumatoid arthritis (RA). There are a number of previous studies of genetic markers in RA, but so far no genetic linkage and only a few associations have been found. Of the associations only one (with the HLA antigen DR4) appears to be well documented. In most previous association studies the patients have not been divided according to sex and family history of RA. In this investigation the HLA antigens A, B and DR and five serum protein systems (Bf, C3, Pi, Hp and Tf) were studied in patients with erosive RA, from northern Sweden. Special attention was paid to variations in the strength of associations according to sex and family history of polyarthritis. The following results were found: The frequency of the HLA antigen B27 was significantly increased in the North-Swedish population (16.6%) and among patients with a family history of polyarthritis (42.6%). In agreement with previous investigations a significantly increased frequency of the DR4 antigen was found in the RA patients. In the properdin factor B (Bf) system the S phenotype was found to be significantly increased in male patients and in patients with a family history of polyarthritis, a more severe form of RA and high titres of rheumatoid factor. No significant differences with respect to phenotype or gene frequencies were found in the C3 complement system. Thus, the association between RA and C3 found in previous investigations was not confirmed. A significant increase of rare alpha-1-antitrypsin (Pi) types (MS, MZ, MF and SZ) was found among RA patients. However, the increase concerned mainly Z heterozygotes and was more strongly pronounced among male patients. In the haptoglobin system a significant increase of the Hp2 gene and the Hp2-2 type was found among patients with a family history of polyarthritis, more pronounced among males. A significant increase of the transferrin gene C2 and of the C2 type was found among male RA patients, more pronounced among patients with a family history of polyarthritis. In 6 out of 8 gene loci studied significant associations were found, which is in agreement with a multifactorial etiology of RA.(ABSTRACT TRUNCATED AT 400 WORDS)

Arthritis, Rheumatoid↗
PubMed1995

Comparative study of four proteases from spent culture media of Porphyromonas gingivalis (FAY-19M-1).

Four gelatin cleaving proteases were partially purified from culture media of Porphyromonas gingivalis (FAY-19M-1) by sequential chromatography on columns of DEAE-Sepharose, Sephadex G-100 and chromatofocusing on PBE-94. The molecular mass of each of these proteases, estimated by relative mobility on gelatin-containing SDS-PAGE, was 50 kDa (Pool D1b), 120 kDa (Pool E1a), approximately 160 kDa (Pool E1b) and > 300 kDa (Pool A1a), respectively. These proteases also differed with respect to charge characteristics, inhibition profile and cleavage specificity. Protease pools A1a and E1a were inhibited by thiol modifying reagents. Protease pool A1a was also inhibited by N-tosyl-L-lysine chloromethyl ketone, and E1a was inhibited by antipain. Protease pool D1b was inhibited by E-64, leupeptin and antipain, and protease E1b was not inhibited by either of these inhibitors. The detailed substrate specificity of these proteases was checked by using chromogenic substrates, synthetic peptides and native proteins. Protease E1b was very active in degrading collagen, fibrinogen, fibronectin, IgG, IgA, third component of complement (C3), serum albumin, transferrin and varies; is directly proportional to 1-acid glycoprotein as substrates. Fibrinogen, fibronectin and complement C3 component were also cleaved by A1a, D1b and E1a. Synthetic peptides insulin B chain, cecropin P-1 and magainin were cleaved by E1b. Based on FAB analysis E1b showed preferential cleavage at hydrophobic or neutral residues. Protease A1a was active towards chromogenic substrates with either lys or arg in P1 position. Protease D1b cleaved chromogenic substrates with arg in P1 position and cleaved synthetic peptides magainin and (KIAGKIA)3-NH2 at lys residues also. Protease E1a showed glycyl-prolyl peptidase activity.

Amino Acid Sequence↗
PubMed2006

Deposition of complement proteins on cells treated by photodynamic therapy in vitro.

Activation of the complement system has emerged as a critical event in the response of tumors to photodynamic therapy (PDT) due to its involvement in the vascular effects as well as in the inflammatory and immune reactions observed with this treatment modality. However, the exact mechanism of PDT-induced complement activation has not been precisely characterized. The present study examines the potential of PDT at the cellular level to directly activate the complement system. Mouse tumor SCCVII cells treated by Photofrin-based PDT and post-incubated in the presence of homologous (mouse) serum were analyzed by flow cytometry for binding of complement proteins on their surface. The results show that PDT induced the fixation of complement C3 protein, probably in the form of its activated fragments, and of the terminal membrane attacks complex of complement on the treated SCCVII cells. Deposition of C3/C3 fragments on human umbilical vein endothelial cells (HUVEC) treated by Photofrin-PDT and post-incubated in the presence of human serum was also detected. Complement fixation was preferentially elevated on SCCVII cell undergoing PDT-induced apoptosis. The induction of surface expression of heat shock protein 70 (HSP70) on PDT-treated cells also triggered complement deposition, since the presence of anti-HSP70 antibodies during the post-PDT incubation blocked the anchoring of C3/C3 fragments to SCCVII cells. The fact that PDT-treated cells are recognized by the complement system as their target adds an important element for understanding the mechanism of tumor response to PDT.

Animals↗