Biomedical subjects

A M Deelder

Publications and source records attributed to A M Deelder.

At least 73 records · Page 4Linked to original sources

PubMed1996

Schistosoma mansoni: in vitro and in vivo excretion of CAA and CCA by developing schistosomula and adult worms.

In this study we describe the excretion patterns of circulating anodic (CAA) and cathodic antigen (CCA) by freshly transformed and developing Schistosoma mansoni schistosomula and adult worms. In vitro, CAA and CCA were excreted by the parasites immediately after transformation. During the first days of development CAA and CCA levels were similar, but after 1 wk more CCA was excreted. Neither feeding the schistosomula with red blood cells nor addition of colchicine influenced the rates of antigen excretion. Female worms produced more antigen than males. In heavily infected mice CCA was the first antigen detectable from the third week of infection onward. A few days later, CAA showed a steep increase, becoming the predominant antigen during the course of infection. In urine samples, obtained at the time of perfusion (7 wk), CCA was the predominant antigen. In conclusion, although CAA and CCA levels in serum and urine generally correlate well with worm burden (as determined by egg output), the present study and a literature review show that the actual quantities produced by the worms and detected in the host circulation or excreta may depend on many factors, e.g., host and parasite species, clearance rates, or duration and intensity of infection.

Animals↗

PubMed1995

Immunoelectron microscopical localization of a circulating antigen in the excretory system of Schistosoma mansoni. Ultrastructural localization studies of the excretory system of S. mansoni.

In this study the excretory system of Schistosoma mansoni was ultrastructurally examined with a recently described monoclonal antibody (mAb) against a circulating antigen. In previous studies this mAb was found to have affinity for the excretory system. Strong immunoreactivity was found on the flagella of the flame cells and of the collecting ducts throughout the worm. The eggshell and the space between the miracidium and the eggshell showed strong reactivity with a declining gradient towards the exterior, suggesting a secretion process. In cercariae, immunoreactivity was restricted to the tegument, whereas in schistosomula the labeling pattern resembled that of the adult worm, demonstrating positive reactivity of the flame cells and no immunostaining of the tegument. This stage-dependent differential expression of different antigens in the excretory system and in the tegument could suggest a maturation process of the excretory system.

Animals↗

PubMed1995

Serum levels of circulating anodic antigen and circulating cathodic antigen detected in mice infected with Schistosoma japonicum or S. mansoni.

Serum concentrations of circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were studied in mice infected with either Schistosoma japonicum or S. mansoni cercariae. Sera from uninfected mice were negative for both antigens. CAA was detectable in the S. japonicum-infected mice as early as at 2 weeks post-infection (p.i.), and levels were higher in these animals than in the S. mansoni-infected group during the full study period. At the moment of perfusion, 10 weeks p.i., a median of 9 and 29 worms, respectively, were recovered from the S. japonicum- and S. mansoni-infected mice, and the median CAA levels were 326 and 27 ng/ml, respectively. In contrast, CCA levels were much lower in the S. japonicum-infected group (27 ng/ml) as compared with the S. mansoni-infected mice (282 ng/ml). These results suggest an important difference between S. japonicum and S. mansoni infections in CAA and CCA production and/or clearance and indicate a significant role for CAA in the diagnosis of human schistosomiasis japonicum.

Animals↗

PubMed1995

Immunodiagnosis of schistosomiasis mansoni in a low endemic area in Surinam by determination of the circulating antigens CAA and CCA.

We evaluated the applicability of circulating antigen detection in serum and urine for the diagnosis of Schistosoma infections in a low endemic area. In total 389 individuals from Saramacca (Surinam) participated in the survey. Stool samples were examined using the Kato method, while circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were determined by highly specific monoclonal antibody-based ELISA's. Also schistosome specific IgM antibodies were measured by the indirect immunofluorescence assay, but the diagnostic performance of this test was found to be poor in this population. S. mansoni eggs were found in 29% of the examined cases, while CAA and CCA could be demonstrated in 23% and 17% of the serum samples and in 3% and 28% of the urine samples, respectively. Forty three percent of the study population was positive in at least one of these diagnostic assays, indicating that each individual test misses a substantial part of the subjects with an active infection. In most positive cases, intensities of infection were very low. As 204 individuals participated in all screening assays, diagnostic performance of each test was evaluated in this sub-population. The highest sensitivities were achieved with the urine-CCA assay and the parasitological examination, detecting 59 and 58 out of the 107 cases with an active infection, respectively. The serum-CAA assay detected 47 positive cases. Our results demonstrate that determination of circulating antigens, especially CCA in urine and CAA in serum, provides information additional to the parasitological examination, for the assessment of prevalence and intensity of Schistosoma infection in low endemic areas.

Adolescent↗

PubMed1995

Optimization of the Magnetic Bead Antigen Capture Enzyme Immuno Assay for the detection of circulating anodic antigens in mixed Schistosoma infections.

In the present study, simplification and adaptation of the Magnetic Bead Antigen Capture Enzyme Immuno Assay (MBAC-EIA) technique for detection of circulating anodic antigens (CAA) under field conditions was achieved. It was shown that the assay could be performed successfully within the broad temperature range of 18-37 degrees C. The slightly lower sensitivity observed at low temperatures could be adjusted for by prolonging the incubation period. Shaking the plate by hand was as good as automatic mechanical shaking, aspiration of the supernatant before the addition of conjugate was not necessary, and the use of whole blood and serum offered similar assay sensitivity. Furthermore incubation times could be considerably shortened without loss of sensitivity. A major advantage of the MBAC-EIA was that the beads, after elution of bound components, were found to be reusable. The study also showed that the sensitivity of the MBAC-EIA technique in diagnosis of schistosomiasis in a Zimbabwean community endemic for both urinary and intestinal schistosomiasis, was 94%.

Adolescent↗

PubMed1995

The relationship between worm burden and levels of a circulating antigen (CAA) of five species of Schistosoma in mice.

This study examines the ability of an assay which measures the amount of a schistosome specific antigen (CAA) in the host circulation to reliably reflect relative worm burden. Mice were infected with 5 species of schistosome with a range of infection dose. The levels of serum CAA increased during schistosome maturation. In all species tested CAA levels correlated well with adult worm burden once the parasites achieved sexual maturity and remained relatively stable during the establishment of egg production. The amount of CAA produced varied between species but within each species CAA levels were proportional to worm numbers: no density-dependent effects on CAA levels were observed even when mice carried worm burdens that were very large relative to host size. T-cell deprivation of the host had no effect on the CAA/worm burden relationship in either Schistosoma mansoni or S. haematobium infections and the CAA equilibrium was unaltered in intact mice when reduction of worm fecundity occurred. These data support the use of the CAA as an accurate and robust estimate of relative schistosome burden in man.

Animals↗

PubMed1995

Ultrastructural immunolocalization of two circulating egg antigens in miracidia of Schistosoma mansoni.

In the present study ultrastructural immunocytochemical techniques have been used to localize the cells producing two soluble egg antigens present in the hatching fluid of Schistosoma mansoni, using two recently described monoclonal antibodies (MAbs). In the miracidium of S. mansoni, the one apical and the two lateral unicellular glands showed immunoreactivity for the egg antigens, using a post-embedding immunogold technique. Immunoreactivity was associated with the contents of vesicles for both the MAbs, although the intravesicular distribution was not identical. This difference in ultrastructural staining pattern provides additional evidence that the two MAbs are binding with different epitopes of the same antigen or with different antigens altogether. The finding of free unbound label around the embedded miracidium is consistent with secretion having been released from the glands.

Animals↗

PubMed1995

Analysis of worm burden variation in human Schistosoma mansoni infections by determination of serum levels of circulating anodic antigen and circulating cathodic antigen.

Serum circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) concentrations, as a possible direct measure of worm burden, were compared with fecal egg counts in a heavily Schistosoma mansoni-infected population from Zaire to allow differentiation between worm loads and worm fecundity in relation to age and intensity of infection. Of the 517 subjects, 95% excreted eggs and 97% demonstrated circulating antigens. Fecal egg counts showed an age-related pattern characteristic for an area in which schistosomiasis is endemic with intense transmission levels. Regression analysis showed that antigen concentrations were strongly associated with egg counts. For CAA, but not for CCA, this relation was found to be nonlinear, which would be consistent with density-dependent fecundity or crowding. The trend was uniform for all age groups, which for this particular population indicated a genuine reduction of worm loads rather than reduced worm fecundity with age of the host.

Adolescent↗

PubMed1995

Glomerulopathy induced by a single monoclonal autoantibody against GP330.

Monoclonal autoantibodies were obtained from Lewis rats with active Heymann nephritis. Two cloned rat/mouse hybridomas, 3D9B and 5B8C, that secreted rat IgG2a autoantibodies were selected for their ability to react with gp330 in ELISA and propagated further. Their specificity was confirmed by immunoprecipitation of crude antigens from a yolk sac carcinoma cell line expressing gp330. The size of the precipitated molecule was identical to that immunoprecipitated by previously described anti-gp330 antibodies. Indirect immuno-electron microscopy showed that 3D9B exclusively stained the intermicrovillous areas of the tubular brush border membrane, while 5B8C stained the full tubular microvillous membrane and the glomerular epithelial coated pits. Passive transfer of 3D9B did not induce Ig deposits or functional renal damage within 7 days. However, injection of 5B8C caused granular glomerular deposits within 1 h, subepithelial immune aggregates within 6 days and antibody deposition on the brush border within 7 days. Only ascites production of clone 5B8C in rats, but not in mice, caused subepithelial immune deposits and abnormal proteinuria. This study shows that a single monoclonal autoantibody to gp330 is able to induce a mild form of Heymann nephritis.

Animals↗

PubMed1995

Epidemiologic application of circulating antigen detection in a recent Schistosoma mansoni focus in northern Senegal.

Quantitative enzyme-linked immunosorbent assays (ELISAs) for the detection of circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) in serum and urine were applied as an epidemiologic tool in a recent, intense focus of Schistosoma mansoni in Senegal. Both CAA and CCA in serum and CCA in urine were found in 94%, 83%, and 95%, respectively, of the population, of which 91% were positive on stool examination. Circulating antigens were also detectable in sera and urines of most egg-negative individuals. The sensitivities of the urine CCA and serum CAA ELISA were substantially higher than that of a single egg count, and increased with egg output. The CAA and CCA levels correlated well with egg counts and with each other. The age-related evolution of antigen levels followed a similar pattern as egg counts, providing supplementary evidence for a genuine reduction of worm burdens in adults in spite of the supposed absence of acquired immunity in this recently exposed community. The antigen:egg ratios decreased in adults, suggesting lower worm fecundity in children. This would be compatible with a density-dependent reduction of fecundity, but not with anti-fecundity immunity in adults that perhaps has not yet developed in this new focus.

Adolescent↗

PubMed1995

Efficacy and side effects of praziquantel in an epidemic focus of Schistosoma mansoni.

Schistosoma mansoni was first reported in the area of Richard Toll (Senegal) in 1988 and spread rapidly in the community, after a series of human-engineered ecologic changes. A random population sample (n = 422) from Ndombo, a village near Richard-Toll, was studied in 1991 by stool examination (four Kato slides from two stool samples) and antigen detection in urine and blood. Stool-positive individuals were treated with 40 mg/kg of praziquantel. A house-to-house interview regarding side effects was conducted 24 hr after treatment. Two hundred ninety-eight subjects were re-examined 10 days (antigen detection) and 12 weeks (egg counts, antigen detection) after treatment. Before treatment, positive egg counts were found in 91% of the subjects, with 41% excreting more than 1,000 eggs per gram (epg) of feces. Treatment of 352 individuals caused serious but transient side effects (colic, vomiting, urticaria, and edema), the frequency of which increased with increasing egg counts. The parasitologic cure rate 12 weeks after treatment was only 18%, the frequency of egg counts with more than 1,000 epg decreased to 5%, and the mean egg count of those remaining positive was reduced by 86%. Antigen detection in serum 10 days and 12 weeks after treatment remained positive in 90% of the subjects, although titers decreased sharply. The low cure rates may be due to intense transmission and/or undeveloped immune responses in this recently exposed population. However, reduced drug susceptibility of the parasite strain has now been confirmed in one local isolate.

Adolescent↗

PubMed1995

[A preliminary report on diagnostic complementarity of gut-associated and egg-associated antigenemia in schistosomiasis japonica].

With Hyroxylapatite purified preparations and BACH (biotin aminocapryl hydrazide) biotinylated McAbs, 274-2H10 and 273-2H1, recognizing different egg-associated epitopes, biotin-avidin (BA) involved alkaline phosphatase (AP) ELISA with detecting sensitivities reaching nanogram levels (10(-9), were set up. The detectable limit for crude preparations of Schistosoma japonicum SEAJ-TCA in 2H10-ELISA achieved 1. 0.3. 2 ng/ml, in which only S. japonicum specific egg antigens were efficiently detected, whereas with 2H1-ELISA, which could detect SEA-TCA of both S. japonicum and S. mansoni species, an end point of detecting 3.2 ng/ml was obtained. Repeated tests with human serum groups revealed very significant differences of extinction OD readings between patients and normal individuals. For detection combinations, a previously established anti-CAA homologous AP-ELISA system was parallelly used for gut-associated antigenemia determinations. Taking the mean extinction OD reading of a parallel normal serum group plus 3 SD as corresponding cut off values, 3 patient groups (n = 82, 52, 39) from different areas of transmission intensity were subjected to accumulating determinations for egg- and gut-associated antigenemia. Improved detectabilities to variable extent were achieved in either of the 2 or 3 combinations. The study thus demonstrated that the diagnostic efficiency for human schistosomiasis could be improved by multi-epitope detections for more than one target molecule using corresponding McAbs, especially in areas where the transmission intensity of the disease is comparatively lower.

Animals↗

PubMed1994

The immunologically reactive part of immunopurified circulating anodic antigen from Schistosoma mansoni is a threonine-linked polysaccharide consisting of --> 6)-(beta-D-GlcpA-(1 --> 3))-beta-D-GalpNAc-(1 --> repeating units.

The gut-associated excretory antigen CAA (circulating anodic antigen) from adult Schistosoma mansoni worms was isolated by immunoaffinity chromatography. Amino acid analysis following alkaline borohydride treatment indicated that CAA is a glycoprotein, O-glycosylated at Thr. The primary structure of the released O-glycan moiety was investigated by one- and two-dimensional, homo- and heteronuclear 1H and 13C NMR spectroscopy. It was found that the major carbohydrate chains have a novel polysaccharide structure, consisting of a branched disaccharide repeating unit containing 2-acetamido-2-deoxy-beta-D- galactopyranose (beta-D-Galp-NAc) and beta-D-glucopyranuronic acid (beta-D-GlcpA). [formula: see text] The major antigenic character of CAA arises from this novel polysaccharide, which was shown to be an absolutely specific diagnostic marker in schistosomiasis. The cross-reactivity of CAA with anti-CCA (circulating cathodic antigen) monoclonal antibodies is caused by the presence of a small amount of O-linked CCA-poly-Lewis x carbohydrate chains on the CAA protein chain.

Animals↗

PubMed1994

The immunologically reactive O-linked polysaccharide chains derived from circulating cathodic antigen isolated from the human blood fluke Schistosoma mansoni have Lewis x as repeating unit.

The gut-associated excretory antigen circulating cathodic antigen (CCA) was isolated by immunoaffinity chromatography from adult Schistosoma mansoni worms, which were collected from infected golden hamsters. This antigen is probably involved in protection of the schistosome gut and is increasingly used in highly sensitive and specific immunodiagnostic assays. Amino acid analysis before and after alkaline borohydride treatment of CCA and monosaccharide analysis indicated that CCA is O-glycosylated mostly via GalNAc-Thr. After reductive alkaline treatment, the O-linked carbohydrate chains were fractionated by gel-permeation chromatography, followed by normal-phase HPLC on LiChrosorb-NH2. Carbohydrate-positive fractions were investigated by one-dimensional and two-dimensional 1H-NMR spectroscopy, fast atom bombardment mass spectrometry and collision-induced-dissociation tandem mass spectrometry. The analyses showed that the low-molecular-mass O-linked oligosaccharide alditols (the minor fraction) consist of disaccharides to hexasaccharides having the Gal beta (1-3)GalNAc-OL core in common. The major carbohydrate fraction comprises a population of polysaccharides, containing Lewis x repeating units (-3)Gal beta (1-4)[Fuc alpha (1-3)]GlcNAc beta (1-). CCA-specific monoclonal antibodies and IgM antibodies in patient sera recognized the fucosylated O-linked carbohydrate antigenic structures. Since CCA evokes a strong IgM antibody response and carbohydrate structures containing repeating Lewis x units are found on circulating neutrophils, it is proposed that the antigenic poly-Lewis x polysaccharide of CCA is involved in the induction of auto-immunity against granulocytes, resulting in the mild to moderate neutropenia observed during schistosome infection.

Animals↗

PubMed1994

A simple technique to pretreat urine and serum samples for quantitation of schistosome circulating anodic and cathodic antigen.

For the detection of the circulating schistosome antigens CAA (circulating anodic antigen) and CCA (circulating cathodic antigen) in serum and urine samples of Schistosoma infected individuals, pretreatment of samples with trichloroacetic acid (TCA) is a standard procedure. In the present study several methods were evaluated in order to develop a more simple and rapid technique than the--especially for pretreatment of urine samples--laborious TCA technique. Optimal results were obtained with a method in which serum or urine samples were pretreated by a heat-incubation step (70 degrees C, 30 min) in an alkaline buffer (pH 9.6). In a comparison of the new technique with the TCA pretreatment, serum and urine samples of S. mansoni infected individuals from Zaire (n = 80) and of uninfected controls from The Netherlands (n = 208) were pretreated and assayed for CAA and CCA. Both pretreatment techniques showed similar sensitivities and specificities for CAA and CCA in serum, and CCA in urine. However, for the determination of CAA in urine the new technique performed significantly better, resulting in an increase of the sensitivity from 32 to 70% (titre determination).

Antigens, Helminth↗

PubMed1994

Evaluation of an ELISA for combined measurement of CAA and CCA in schistosomiasis mansoni.

An enzyme-linked immunosorbent assay was developed for combined measurement of schistosome circulating anodic antigen (CAA) and circulating cathodic antigen (CCA). Monoclonal antibodies against CAA and CCA were used as coating and as fluorescein-labeled detecting antibodies in a FITC-anti-FITC system. The lower detection limit of the assay was 1.1 ng antigen (AWA-TCA)/ml. Serum samples of Schistosoma mansoni infected individuals from Zaire (n = 60) and Burundi (n = 60) were tested in this assay and in single-antigen ELISAs. Sensitivities of assaying for CAA, CCA, combined CAA + CCA, and of parallel testing for CAA and for CCA were calculated from titres and antigen concentrations. With serum samples from the heavily infected individuals (Zaire), all assays had a sensitivity of 97% or higher. In contrast, with serum samples from individuals from Burundi (low to moderate infections) it was shown that combined testing resulted in a slightly lower sensitivity than testing for individual antigens. By parallel testing for CAA and CCA, the sensitivity could be increased considerably (to 95%), however.

Animals↗

PubMed1994

Monitoring the efficacy of different doses of praziquantel by quantification of circulating antigens in serum and urine of schistosomiasis patients.

We evaluated the quantitation of two schistosome circulating antigens in serum and urine as a tool for the assessment of the efficacy of praziquantel dosage regimens (40 versus 60 mg/kgbw). In addition we compared the efficacy of two different brands of praziquantel (Biltricide and Distocide), given at the same dosage (40 mg/kgbw). Thirty five Egyptian hospitalized schistosomiasis mansoni patients participated in this study. Thirteen patients (Group 1) received 60 mg/kgbw Biltricide, administered in 3 oral doses of 20 mg in one day; 22 individuals (Group 2) were treated with 40 mg/kgbw (12 Biltricide, 10 Distocide), given in one oral dose. Circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were quantitated by monoclonal antibody-based ELISA's before, and 1, 3 and 6 weeks after chemotherapy. Before treatment, all patients were positive for at least one of the circulating antigen assays. Three to six weeks after treatment significantly more patients were found to be negative in Group 1 compared to Group 2 (X2 = 7.13, P = 0.008, n = 35). Also the levels of CCA and CAA in serum and of CCA in urine were found to be significantly higher in Group 2 (Mann-Whitney U < 85, P < 0.05, n = 35). These results were confirmed by parasitological data. No differences were found between treatment with Biltricide or Distocide.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1994

Circulating anodic and cathodic antigen in serum and urine from Schistosoma haematobium-infected Cameroonian children receiving praziquantel: a longitudinal study.

A cohort of 148 Cameroonian children infected with Schistosoma haematobium was followed before praziquantel therapy and 1, 2, 3, 5, and 12 months thereafter. Egg output, the reagent strip index (RSI, a pathological marker), and circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) in serum and urine were quantified. At enrollment, the median level of egg output was 365/10 mL of urine; 97% of children had a positive RSI; CAA was detected in serum from 76% of children and in urine from 64%; and CCA was detected in serum from 55% of children and in urine from 87%. Two months after chemotherapy, egg output and RSI had decreased significantly; reinfection later developed in parallel with increases in the serum and urine concentrations of CAA and the urine concentrations of CCA. The measurement of CAA and CCA is useful for diagnosis, evaluation of disease severity, and follow-up of chemotherapy in individuals infected with S. haematobium.

Adolescent↗