Changes in the physicochemical and enzymic properties of myosin during ontogeny

During development of the calf fetus two forms of fetal myosin appear. The form of myosin characteristic of the skeletal muscle of the calf fetus at 2.5–6 months of development, not present in the later stages, is salted out with ammonium sulfate in a saturation of up to 25%; it has low ATPase activity and is easily denatured. The cholinesterase activity of the myofibrils is connected with this myosin fraction. The second form of fetal myosin is relatively stable, it has much higher ATPase activity, and it is salted out with ammonium sulfate in saturations of 35–50%. Both forms of myosin are found in the early stages of development of the calf fetus, but only the second form in the later stages. By electrophoresis in polyacrylamide gel marked heterogeneity is found in the region of the heavy components infetal myosin solutions obtained in the early periods of development.     

Comparison of the immune response to sheep erythrocytes,tetanus toxoid and endotoxin in different strains of mice

The primary immune response in 7 inbred and 2 outbred mouse strains to SRBC, tetanus toxin and ‘E.coli’ endotoxin is compared. Significant variations are found in the different strains concerning their antibody response to these antigens. The differences in antibody production reached with SRBC (direct and indirect PFC) and tetanus toxin are on a quantitative level, those with endotoxin also on a qualitative level. The kinetic studies further indicate that course of antibody formation as well as peak of response may considerably vary between different strains.     

In Vivo and In Vitro Immunomodulatory Potential of Swertiamarin Isolated from Enicostema axillare (Lam.) A. Raynal That Acts as an Anti-inflammatory Agent

Swertiamarin is a secoiridoid glycoside found in Enicostema axillare (Lam) A. Raynal, a medicinal plant used as a depurative in the Indian system of traditional medicine. The present study evaluated the immunomodulatory activity of isolated swertiamarin. In vivo immunomodulatory activity of swertiamarin (2, 5, and 10 mg/kg b.w.) was evaluated in a model of sheep red blood cells (SRBC) by assessing its effect on organ weight, hemagglutinating antibody titer (HA), plaque-forming cells (PFC), quantitative hemolysis of SRBC, and delayed type hypersensitivity (DTH). In vitro immunomodulatory potential was studied on isolated splenocytes, neutrophils, and peritoneal macrophages. In silico immunomodulatory effects were evaluated by docking of swertiamarin on proinflammatory cytokines to confirm its potential. In in vivo studies, the animals treated with swertiamarin showed a significant (P?≤?0.05) increase in antibody titer, plaque-forming cells, and also in weight of the thymus and spleen. A decreased response to DTH reaction was recorded with the treatment of swertiamarin. In in vitro studies, treatment with swertiamarin modulated the messenger RNA (mRNA) and protein expression of IFN-γ, IL-10, and IL-4 significantly (P?≤?0.05) and also favored Th2-mediated response on concanavalin A (Con A)-induced splenocytes. The compound inhibited the release of free radicals significantly (P?≤?0.05) in phytohemagglutinin (PHA)-induced neutrophils and also ameliorated the mRNA and protein expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) in lipopolysaccharide (LPS)-induced macrophages. In in silico, the best docked pose of swertiamarin with the target proteins (TNF-α, IL-1β, and IL-6) was confirmed that swertiamarin acted as an anti-inflammatory mediator.     

Functional competence and monoclonal antibody reactivity of neutrophils from cows injected with Escherichia coli endotoxin

Neutrophils of cows injected with endotoxin were evaluated for their functional competence and monoclonal antibody binding in relation to morphological maturity. Six clinically healthy lactating Holstein cows were each injected intravenously with 100 μg Escherichia coli endotoxin. Blood was collected at 0, 6, 30, 54, 78 and 150 hours postinjection for total and differential leucocyte counts and to isolate neutrophils for functional assays. Marked leucopenia, neutropenia with left shift to band neutrophils, lymphopenia and monocytopenia were evident at 6 h postinjection. Neutrophil and lymphocyte counts normalised by 30 hours, while band neutrophils remained elevated until 54 hours postinjection. Neutrophils isolated at 6, 30 and 54 hours postinjection revealed significantly increased relative phagocytic index, reduced chemotactic activity, and increased binding of a bovine neutrophil monoclonal antibody (36H10). Ingested bacteria per cell were increased at 6 hours. Phorbol myristate acetate-induced oxidative product formation was significantly reduced at 30 hours, but chemiluminescence activity did not change significantly. In vivo binding of autologous IgG₂ and IgA to neutrophils significantly decreased at 30 and 54 hours and IgM binding was reduced at 78 hours postinjection. Band neutrophils were chemotactically and phagocytically less active than segmented neutrophils. The number of band neutrophils in blood correlated directly with the relative phagocytic index and the percentage of cells binding monoclonal antibody 361110 and inversely with the chemotactic activity of neutrophils. These observations indicate that functional heterogeneity of bovine neutrophils can be attributed, at least in part, to morphological maturity of cells and to differences in expression of surface antigens.     

Increased Prevalence of Gastrointestinal Viruses and Diminished Secretory Immunoglobulin a Levels in Antibody Deficiencies

Purpose

Gastrointestinal disease occurs frequently in antibody deficiencies. This study aims to explore the relation between gastrointestinal infections and mucosal homeostasis in patients with antibody deficiencies.

Methods

We performed an observational study including 54 pediatric antibody deficient patients (48 % CVID, 41 % CVID-like, 11 % XLA) and 66 healthy controls. Clinical symptom scores and stool samples were collected prospectively. Stool samples were evaluated for bacteria, parasites, viruses, secretory IgA- and for calprotectin levels. Results were compared between patients and controls.

Results

24 % of antibody deficient patients versus 9 % of healthy controls tested positive for gastrointestinal viruses (p?=?0.028). Fecal calprotectin levels were significantly higher in virus positive patients compared to virus negative patients (p?=?0.002). However, in controls, fecal calprotectin levels were similar between virus positive and virus negative controls. Moreover, gastrointestinal virus positive patients had low serum IgA levels in 13/14 cases (94 %) versus 40/62 (62 %) patients in the virus negative patient group (p?=?0.04). The virus positive patient group also displayed significantly lower secretory IgA levels in stool (median 13 ug/ml) than patients without gastrointestinal viruses detected or healthy controls (median 155 ug/ml) (p?=?0.046).

Conclusion

We here report an increased prevalence of gastrointestinal viruses and gastrointestinal complaints in antibody deficient patients. Patients that tested positive for gastrointestinal viruses showed diminished serum- and secretory IgA levels, and only in patients, virus positivity was associated with signs of mucosal inflammation. These findings suggest that particularly patients with low IgA are at risk for longstanding replication of gastrointestinal viruses, which may eventually result in CVID-related enteropathy.     

Optimisation of Omalizumab Dosage in Patients with Severe Persistent Allergic Asthma Using recoveryELISA

Background

The objective of this study was to investigate the suitability of recoveryELISA as a method to monitor treatment with therapeutic antibodies using the example of omalizumab.

Methods

The recoveryELISA is a newly developed immunoassay technology that measures three parameters in one test: the free level of antigen, the level of therapeutic antibody and the specific dose-response interaction which represents the actual activity of the drug. A retrospective and observational analysis was performed on 197 serum samples from 17 patients (13 ± 4 years of age) with severe persistent allergic asthma who received add-on treatment with omalizumab.

Results

The mean omalizumab serum level during antibody therapy was 59 ± 45 µg/mL; the kit’s upper detection limit of 140 µg/mL was exceeded in 27 samples. Antibody concentrations between 50 and 140 µg/mL were found in 64 samples. Independent of the omalizumab dosage, nearly all measurements were in a range of absolute saturation as regards the IgE binding rate. Almost complete binding of IgE with a recovery of added labelled IgE of <1 % was reached within a maximum of 11 days.

Conclusions

The biochemical activity of therapeutic antibodies can be examined by recoveryELISA and their residual activity can be determined. Thus, further individualisation of therapy with biologics is possible using this test which seems to be suitable to diminish side effects and reduce costs.     

Evaluation of seed extracts from plants found in the Caatinga biome for the control of Aedes aegypti

Dengue fever, currently the most important arbovirus, is transmitted by the bite of the Aedes aegypti mosquito. Given the absence of a prophylactic vaccine, the disease can only be controlled by combating the vector insect. However, increasing reports of resistance and environmental damage caused by insecticides have led to the urgent search for new safer alternatives. In this regard, plants stand out as a source of easy-to-obtain biodegradable insecticide molecules. Twenty (20) plant seed extracts from the Caatinga, an exclusively Brazilian biome, were prepared. Sodium phosphate (50 mM, pH 8.0) was used as extractor. The extracts were used in bioassays and submitted to partial characterisation. A Probit analysis of insecticides was carried out, and intergroup differences were verified by the Student’s t test and ANOVA. All the extracts exhibited larvicidal and ovipositional deterrence activity. The extracts of Amburana cearenses, Piptadenia viridiflora, Erythrina velutina, Myracrodruon urundeuva and Schinopsis brasiliensis were also pupicides, while the extracts of P. viridiflora, E. velutina, A. cearenses, Anadenanthera colubrina, Diocleia grandiflora, Bauhinia cheilantha, Senna spectabilis, Caesalpinia pyramidalis, Mimosa regnelli and Genipa americana displayed adulticidal activity. Egg laying was compromised when females were fed extracts of Ricinus communis, Croton sonderianus and S. brasiliensis. At least two proteins with insecticidal activity were found in all the extracts. Phenol compounds were identified in all the extracts and flavonoids, triterpenes or alkaloids in 14 of them. The results show the potential of plant seed extracts from the Caatinga as a source of active molecules against A. aegypti mosquitos.     

Improve immunogenicity of DNA vaccine against foot-and-mouth disease virus: Role of intron and probably viral 3C protease as biological adjuvants

Foot-and-mouth disease (FMD) is one of the most important diseases with heavy economic losses. The causative agent of the disease is a virus, named as FMD virus, belonging to the picornavirus family. There is no treatment for the disease and vaccination is the main control strategy. Several vaccination methods have been introduced against FMD including DNA vaccines. In this study, two genetic constructs, which were defined by absence and presence of an intron, were tested for their ability to induce the anti-FMD virus responses in mouse. Both constructs encoded a fusion protein consisting of viral (P12A and 3C) and EGFP proteins under the control of CMV promoter. The protein expression was studied in the COS-7 cells transfected with the plasmids by detecting EGFP protein. Cell death was induced in the cells expressing the P12A3C-EGFP, but not the EGFP, protein. This might be explained by the protease activity of the 3C protein which cleaved critical proteins of the host cells. Mice injected with the intron-containing plasmid induced 16-fold higher antibody level than the intronless plasmid. In addition, serum neutralization antibodies were only induced in the mice injected with intron-containing plasmid. In conclusion, the use of intron might be a useful strategy for enhancing antibody responses by DNA vaccines. Moreover, cell death inducing activity of the 3C protein might suggest applying it along with DNA vaccines to improve immunogenicity.     

Sorcin antibody as a possible predictive factor in conversion from radiologically isolated syndrome to multiple sclerosis: a preliminary study

Objective

To identify an antibody biomarker for prediction of conversion from radiologically isolated syndrome (RIS) to relapsing remitting multiple sclerosis (RRMS).

Methods

Sera of 13 RIS patients were screened by a protein macroarray derived from human fetal brain cDNA library.

Results

Sequencing of a clone with the highest signal intensity revealed sorcin as a potential target autoantigen in RIS patients. ELISA studies showed high-titer sorcin-antibodies in 3 of 4 RIS patients who converted to RRMS in a 5-year follow-up period and 13 of 23 control RRMS patients.

Conclusion

The value of sorcin antibody as a predictor of conversion from RIS to RRMS requires to be tested in larger prospective studies.     

Action of histamine and 3-isobutyl-1-methylxanthine on cAMP activation of protein kinase in dog gastric mucosa

Dog gastric mucosa was incubated with histamine, IMX and db-cAMP, and the tissue was analyzed for cAMP content and cAMP-dependent protein kinase activity. Results show that in the absence of IMX, histamine does not produce measurable changes in either cAMP content or protein kinase activity ratios. In the presence of 5×10^?5 mol/I IMX histamine elicits a dose-dependent accumulation of cAMP, and this accumulation is reflected in elevated protein kinase activity ratios. When IMX concentration is increased to 5×10^?4 mol/l, the histamine effect is more pronounced. Incubation of gastric mucosa with 10^?6 mol/l db-cAMP results in elevated cAMP tissue levels both in the absence and presence of IMX, but protein kinase activity ratio is significantly elevated only in the presence of 5×10^?4 mol/l IMX. It is concluded that histamlen stimulates cAMP formation and protein kinase activation in dog gastric mucosa, but elevations are detectable only when the phosphodiesterase enzyme is inhibited.     

Grounds for using Pierre's method of ACTH estimation in human blood plasma

Rat adrenal glands were immersed in Ringer-Locke solution (control) and, in parallel tests, in human blood plasma. After incubation for 2 h the corticosterone concentration in the extracts was determined. Activity of the pituitary adrenocorticotropic function of the patients tested was judged from the difference between the corticosterone values in the experimental and control extracts. To determine the sensitivity of the method ACTH was added to blood plasma in doses of 1, 5, and 10 μg. A significant and regular increase in the corticosterone concentration was found. The modification of Pierre's method is perfectly suitable for the estimation of ACTH in man.     

Properties of lymphocyte chemotactic factor (lymphotactin) in thymus

Aqueous extracts of calf thymus from immunologically stimulated animals contain trypsin- and neuraminidase-labile macromolecules with molecular weights of less than 30,000 daltons which will specifically attract chemotactically lymphocytes. This activity we ascribe to lymphotactin.Supported in part by a contract from the Office of Naval Research N00014-71-C-0203.     

Enzyme-linked immunosorbent assay for detection of solubleToxoplasma gondii antigen in acute-phase toxoplasmosis

Sixty-two sera from 51 patients with lymphadenopathy presumed to be due to acute-phase toxoplasmosis were tested for specific IgM class antibodies by both the immunofluorescence antibody toToxoplasma gondii in sera were first dissociated in 3M NaSCN. Antigen attached to the solid phase was detected with enzyme-coupled IgG antibody toToxoplasma antibody toToxoplasma gondii in sera were first dissociated in 3M NaSCN. Antigen attached to the solid phase was detected with enzyme-coupled IgG antibody toToxoplasma gondii. Neither hepatitis B surface antigen nor antigen ofMycoplasma pneumoniae, rubella, cytomegalovirus or herpes simplex virus interfered with this ELISA. Soluble antigen was detected in 13(30%) of 42 IgM-positive acute-phase toxoplasmosis patients and in only one of 20 sera cleared of IgM. None of an additional 44 IgM-negative patients with low IgG titres had a positive result in the antigen ELISA. Follow-up studies in four acute-phase toxoplasmosis patients showed that the soluble antigen cleared in all cases before the specific IgM antibodies. Simultaneous detection of IgM antibodies toToxoplasma gondii and soluble antigen would thus seem to indicate an early stage of the infection.     

Increased levels of anti-heat-shock protein 60 (anti-Hsp60) indicate endothelial dysfunction,atherosclerosis and cardiovascular diseases in patients with mixed connective tissue disease

Heat-shock protein 60 (Hsp60) has been shown to provoke inflammation, and anti-Hsp60 may facilitate the development of atherosclerosis. In this study, we have investigated 30 patients with mixed connective tissue disease (MCTD) and assessed anti-Hsp60 and their relationship to cardiovascular diseases (CVD). Out of 30 patients with MCTD, 15 had CVDs. Anti-Hsp60 antibody was determined by enzyme-linked immunosorbent assay. Since endothelial dysfunction and accelerated atherosclerosis are characteristic to MCTD, a wide array of MCTD-, endothelial dysfunction- and CVD-associated parameters was investigated: serum lipid levels, paraoxonase activity (PON1), rich nuclear ribonucleoprotein U1 (anti-U1RNP), anti-endothelial cell antibodies, anti-cardiolipin and anti-β2-glycoprotein I antibody isotypes (anti-CL and anti-β2GPI), endothelin-1 (ET-1) levels, also intima–media thickness (IMT), a quantitative indicator of atherosclerosis. In MCTD, anti-Hsp60 antibody levels were significantly higher than in healthy individuals (p < 0.02). MCTD patients with CVD had significantly higher levels of anti-Hsp60 compared to MCTD without CVD (p = 0.001). Patients with MCTD had significantly lower high-density lipoprotein cholesterol (p = 0.02) and PON activity (p < 0.001), and significantly increased systolic (p < 0.0002) and diastolic (p < 0.001) blood pressure compared to healthy individuals. Anti-U1RNP levels (p < 0.002) and IMT were higher in patients compared to controls (p = 0.002). The CVD-positive MCTD patients had increased anti-Hsp60 (p < 0.0013), anti-CL IgG (p = 0.0005), ET-1 serum concentration (p < 0.05) and IMT levels (p < 0.001) compared to MCTD patients without CVD. Anti-Hsp60 showed a strong correlation with anti-oxLDL (r = 0.36, p = 0.01) and serum ET-1 (r = 0.62, p < 0.001) and negative correlation with PON activity (r = ?0.47, p = 0.01). Anti-Hsp60 indicates endothelial injury, CVD, and can function as a novel atherosclerotic risk factor, also a valuable diagnostic marker in patients with MCTD.     

Enzyme-linked immunosorbent assay for detection of immunoglobulin G and M antibodies to teichoic acid in intravascular staphylococcal disease

An enzyme-linked immunosorbent assay (ELISA) for detection of IgG and IgM antibodies to cell-wall teichoic acids ofStaphylococcus aureus and three defined coagulase-negative staphylococci was tested using serum samples from 11 cases of intravascular coagulasenegative staphylococcal infections, 13 cases ofStaphylococcus aureus endocarditis, and 24 patients with no evidence of infection. IgG antibody titers to all four teichoic acids in the 13 patients withStaphylococcus aureus endocarditis were significantly different from those in noninfected control patients (p<0.0001). In contrast, IgG antibody titers in serum from 11 cases of intravascular coagulase-negative Staphylococcal infection were not significantly different from those in control sera. There were no differences in IgM antibody titers of the three groups. Although the ELISA was sensitive in detectingStaphylococcus aureus endocarditis, it was not reliable in the detection of intravascular coagulasenegative Staphylococcal infections, even when tested with specific teichoic acid.     

Regulation of glucose 6-phosphate dehydrogenase expression in CHO-human fibroblast somatic cell hybrids

Human-hamster somatic cell hybrids have been obtained by fusion of a CHO line (NA31) doubly deficient in hypoxanthine guanine phosphoribosyltransferase and glucose 6-phosphate dehydrogenase (G6PD) with normal G6PD(+) human fibroblasts. Analysis of NA31 extracts has revealed that, although G6PD activity is nearly absent, significant activity can be detected with 2-deoxyglucose 6-phosphate as substrate, so that the mutant and normal forms of the enzyme can both be easily detected. The cell hybrids obtained express human G6PD. The human G6PD subunits are distributed in homodimeric molecules as well as in human-hamster heterodimeric molecules. However, whereas the amount of hamster G6PD subunits present in the hybrid is similar to that in the hamster parental cells, the amount of human G6PD subunits is decreased by 3- to 10-fold when compared to the human parental cell. These results indicate that either the expression of the G6PD gene or the stability of the gene product is altered in the hybrid. By mutagenesis and selection in diamide (a substance that oxidizes intracellular glutathione), we have isolated a clone with a 3- to 5-fold increase in human G6PD activity. This derivative may have an increased rate of expression of the human G6PD structural gene.     

An anti-human immunoglobulin M monoclonal antibody for detection of antibodies toToxoplasma gondii

An anti-human μ-chain monoclonal antibody, Tibi 82, was produced and tested for specificity by radioimmunoassay. Its reliability in detecting IgM antibodies toToxoplasma gondii was tested by two reverse immunosorbent methods (IgM-ISAGA and IgM-SPIHA) and the IgM fluorescent antibody test (IgM-IFA) on 400 sera. Whereas the results obtained with Tibi 82 and with two polyclonal reagents were highly correlated, the third commercial polyclonal reagent provided many false negative results. By standardizing IgM binding, Tibi 82 allowed the comparison of IgM-ISAGA with IgM-SPIHA on 100 sera: 17 % of the sera tested showed discrepancies due to the different toxoplasma antigens used. Although Tibi 82 facilitated the reading of results and enhanced sensitivity and specificity of the double-sandwich IgM-IFA method, the latter was still less sensitive than IgM-ISAGA with Tibi 82. Tests with the monoclonal antibody were consistently superior to tests with polyclonal antibodies.     

Time courses of antibody levels inMastomys natalensis after infections withLitomosoides carinii,dipetalonema viteae,brugia malayi orB. pahangi,determined by ELISA

Using aLitomosoides carinii adult antigen, time courses of antibody levels were followed by an ELISA inL. carinii, Dipetalonema viteae, Brugia malayi andB. pahangi infectedMastomys natalensis. Using various groups of infected animals, periods up to 400 days after infection were covered. InL. carinii infected Mastomys, antibodies were first detected 11 days p.i. and levels increased rapidly until day 40. Temporarily reduced levels about the beginning of patency were followed by increasing values until about 100 days p.i. Then the antibody content of the sera remained more or less constant until about 250 days p.i. although maximum levels were found at day 170. Thereafter, the antibody concentration in the sera declined slowly but high levels were still observed 390 days p.i. The antibody content was usually higher in animals with high microfilariae densities than in those with low microfilariae counts but relations could not be proven statistically. InD. viteae infected Mastomys, maximum antibody values were reached within the beginning of patency. Levels were not altered markedly until about 110 days p.i. Thereafter they decreased slightly but then remained constant until the end of the investigation period 350 days p.i. B. malayi infected animals showed a rapid increase of the antibody content in the sera; a maximum was reached by 20 days after the infection. Thereafter, somewhat constant levels were found for 4–5 months. After 200 days p.i. the antibody levels declined progressively, accompanied with increasing parasitaemia densities; after 380 days the levels reached about 2/3 of the maximum. However, despite this, no relation was found between the levels of parasitaemia and antibody in individual animals. InB. pahangi infections the main prepatent antibody increase occurred during week 5 p.i., when maximum values were observed. The beginning of patency and the early patency were accompanied with slightly declining antibody levels. From 150 days p.i. until the end of the investigation 400 days p.i., the antibody content of the sera was fairly constant.     

Isolation and characterization of interspecific heat-resistant hybrids between a temperature-sensitive Chinese hamster cell asparaginyl-tRNA synthetase mutant and normal human leukocytes: Assignment of humanasnS gene to chromosome 18

We isolated interspecific somatic cell hybrids between human peripheral leukocytes and a temperature-sensitive CHO cell line with a thermolabile asparaginyl-tRNA synthetase. The hybrids were selected at 39° C so as to require the expression of the human gene complementing the deficient CHO enzyme. In vitro heat-inactivation profiles of cell-free extracts from temperature-resistant hybrid cells indicate the presence of two forms of asparaginyl-tRNA synthetase. One form is very resistant to thermal inactivation, like the normal human enzyme, while the other form is very thermolabile, like the altered enzyme from the CHO parent. Hybrids and temperature-sensitive segregants derived from them were analyzed for the expression of known human chromosomal marker enzymes. The strong correlation between the expression of the human form of asparaginyl-tRNA synthetase and the presence of human chromosome 18 in hybrids suggests that the human gene, asnS,which corrects the heat-sensitive phenotype of the CHO asparaginyl-tRNA synthetase mutant, is located on chromosome 18.     

Evaluation of the sensitivity of IgG and IgM ELISA in detecting Schistosoma mansoni infections in a low endemicity setting

Schistosomiasis is a major public health concern, with 200 million people infected worldwide. In Brazil, this disease has been reported in 19 states, and its prevalence in the city of Barra Mansa in Rio de Janeiro State is 1 %. The parasitological diagnostic methods currently available in these areas lack sensitivity; however, enzyme-linked immunosorbent assays (ELISAs) have been employed successfully for the diagnosis of schistosomiasis by using antibodies against antigens of Schistosoma mansoni adult worms and eggs, and for the detection of circulating antigens. The objective of this study was to determine systematically the prevalence of S. mansoni infection in the peripheral areas of Barra Mansa. A cross-sectional study was conducted from April to December 2011 by using probabilistic sampling that collected 610 fecal samples and 612 serum samples. ELISA-IgG with total extracts and ELISA-IgM with trichloroacetic acid-soluble fractions were employed to detect antibodies against S. mansoni and were compared with the Kato–Katz and Hoffman parasitological techniques. Among the individuals studied, anti-S. mansoni antibodies were detected in 11.16 % (n?=?71) by ELISA-IgG and in 20.75 % (n?=?132) by ELISA-IgM, while the parasitological techniques showed 0.82 % (n?=?5) positivity. The agreement between the two ELISA tests was 85.38 % (n?=?543), and 8.65 % (n?=?55) of the serum samples showed positive results in both tests. The higher positivity of the ELISA-IgM test corroborates the results of previous reports and indicates that the test may be a useful tool in epidemiological studies, particularly in areas of low endemicity for S. mansoni.