A multihousehold study reveals a positive correlation between age, severity of ocular toxoplasmosis, and levels of glycoinositolphospholipid-specific immunoglobulin A.

A cross-sectional household study involving 499 individuals was undertaken in an area of Minas Gerais state, Brazil, where infection with Toxoplasma gondii is endemic. Nearly 50% (n=247) of the sample had T. gondii-specific antibodies, even individuals in the 5-9-year-old age group.

Cross-reactivity of Schistosoma mansoni cytosolic superoxide dismutase, a protective vaccine candidate, with host superoxide dismutase and identification of parasite-specific B epitopes.

Schistosoma mansoni, an intravascular parasite, has evolved a number of immune evasion mechanisms to establish itself in the host, such as antioxidant enzymes. Our laboratory has demonstrated that the highest levels of certain antioxidant enzymes are found in adult worms, which are the least susceptible to immune killing. Vaccination of mice with naked DNA constructs containing the gene encoding Cu/Zn cytosolic superoxide dismutase (SmCT-SOD) showed significant levels of protection compared to a control group, and our data demonstrate that the adult worms are a target of the immune response that confers resistance in SmCT-SOD DNA-vaccinated mice.

Cellular responses and cytokine production in post-treatment hookworm patients from an endemic area in Brazil.

Human hookworm infections are distributed widely in tropical areas and have a significant impact on host morbidity and human health. In the present study, we investigated the cellular responsiveness and cytokine production in peripheral blood mononuclear cells (PBMC) from Necator americanus-infected schoolchildren who had recently received chemotherapy, and compared them with non-infected endemic controls. Hookworm patients and treated, egg-negative individuals showed a lower cellular reactivity against phytohaemagglutinin (PHA) and hookworm antigen when compared with egg-negative endemic controls.

Exposure to Schistosoma mansoni infection in a rural area in Brazil. Part III: household aggregation of water-contact behaviour.

Much research points to the importance of the household in the study of water-borne diseases such as schistosomiasis. An important aspect of the household is the clustering of domestic activities associated with water collection, storage and usage. Such activities can result in the sharing of water-contact sites and water-contact behaviour, which expose household members to similar risks of infection.

Chemokine receptor expression on the surface of peripheral blood mononuclear cells in Chagas disease.

We evaluated the expression of chemokine receptors (CCR1, CCR2, CCR5, and CXCR4) on the surface of peripheral blood mononuclear cells obtained from patients with chronic chagasic cardiomyopathy (CCC) and noninfected individuals. Only CCR5 and CXCR4 expression was different on the surface of the subsets (CD4, CD8, and CD14) evaluated. Patients with mild CCC had elevated leukocyte expression of CCR5, compared with noninfected individuals or those with severe disease.

Phenotypic features of peripheral blood leucocytes during early stages of human infection with Trypanosoma cruzi.

We performed a cross-sectional flow cytometric analysis of peripheral blood mononuclear cells to evaluate human immunologic status during early stages of Trypanosoma cruzi infection in children. We identified major immunological features corresponding to three proposed phases of disease: early acute (EA) phase, late acute (LA) phase and recent chronic (RC) phase. EA phase was accompanied by expansion of conventional B cells, up-regulation of CD54 on monocytes and down-regulation of CD54 on T cells and not associated with monocyte-activation phenotypes or changes of natural killer (NK) population.

Transmission of Helicobacter pylori infection in families of preschool-aged children from Minas Gerais, Brazil.

We evaluated the role of the family in the transmission of Helicobacter pylori infection in preschool-aged children from a rural district in the State of Minas Gerais, Brazil. Sixty-six families (66 index children, 63 mothers, 60 fathers and 134 siblings), defined as at least one parent living in the same household with at least one offspring up to 8 years old, were studied. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression controlling for age, gender, number of children in household and H.

Short report: quantification of leishmaniavirus RNA in clinical samples and its possible role in pathogenesis.

Leishmaniavirus (LRV) is a double-stranded RNA virus that infects the protozoa Leishmania and has been identified in numerous strains of Leishmania braziliensis and L. braziliensis guyanensis. In general, the species of Leishmania dictates disease manifestation except in the case of L.

Myriadenolide, a labdane diterpene isolated from Alomia myriadenia (asteraceae) induces depolarization of mitochondrial membranes and apoptosis associated with activation of caspases-8, -9, and -3 in Jurkat and THP-1 cells.

Myriadenolide is a diterpene that we have recently isolated from the extract of Alomia myriadenia (Asteraceae). Here we show for the first time that myriadenolide has caspase-dependent cytotoxic activity against human leukemia cells from both lymphocytic (Jurkat) and monocytic (THP-1) lineages, because preincubation of Jurkat or THP-1 cells with the broad-spectrum caspase inhibitor z-VAD-fmk completely abrogated cell death. Moreover, the mitochondrial pathway is implicated as mitochondrial depolarization and caspase-9 and caspase-3 activation were observed.

Progress in the development of a recombinant vaccine for human hookworm disease: the Human Hookworm Vaccine Initiative.

Hookworm infection is one of the most important parasitic infections of humans, possibly outranked only by malaria as a cause of misery and suffering. An estimated 1.2 billion people are infected with hookworm in areas of rural poverty in the tropics and subtropics.

Evaluation of the immune response to CRA and FRA recombinant antigens of Trypanosoma cruzi in C57BL/6 mice.

Humoral and cellular immune responses were evaluated in 44 C57BL/6 mice immunized with the Trypanosoma cruzi recombinant antigens CRA and FRA. Both antigens induced cutaneous immediate-type hypersensitivity response. The levels of IgG1, IgG2a, IgG2b and IgG3 were high in CRA immunized mice.

Immunity to schistosomiasis: glycans are potential antigenic targets for immune intervention.

The major humoral immune responses in animals infected with Schistosoma mansoni are directed toward carbohydrate antigens. Among these antigens are complex-type N-glycans expressing LDN [GalNAcbeta1-4GlcNAc-R], LDNF [GalNAcbeta1-4(Fucalpha1-3)GlcNAc-R], and polymeric Lewis x (Lex) [Galbeta1-4(Fucalpha1-3)GlcNAc]n-R epitopes. We have now evaluated the potential of the three glycan antigens as targets for immune-mediated intervention of infections and serodiagnosis.

Genetic epidemiology of Trypanosoma cruzi infection and Chagas' disease.

Chagas' disease is a leading cause of heart disease throughout Latin America, affecting an estimated 16 to 18 million individuals. Given the large pool of primary hosts for this zoonotic disease, complete eradication of Chagas' disease through control of the arthropod vector is unlikely. Research with both humans and animal models indicates that there is considerable variation in susceptibility to infection and disease outcome, and that this variation may be due in part to genetic factors.

Cellular responses and cytokine profiles in Ascaris lumbricoides and Trichuris trichiura infected patients.

The impact of intestinal helminth infection, i.e. Ascaris lumbricoides and Trichuris trichiura, on cellular responsiveness and cytokine production was investigated in young adults.

P38 mitogen-activated protein kinase influence on the production of IL-10 in human schistosomiasis mansoni.

Schistosomiasis mansoni remains a significant public health problem in many parts of the tropics and subtropics. Clinical manifestations range from the asymptomatic intestinal form through to the hepatosplenic form of the disease, a potentially lethal clinical condition in a subsection of the exposed population. In this study, we investigated the mechanisms by which interleukin (IL)-10 production could be differentially controlled in patients with the intestinal and hepatosplenic forms of the disease, as IL-10 may play a fundamental role in the development of the hepatosplenic disease state.

In vitro activity of labdane diterpene from Alomia myriadenia (Asteraceae): immunosuppression via induction of apoptosis in monocytes.

A screening program in Brazilian flora was carried out to detect the presence of immunosuppressive compounds by using the in vitro phytohemagglutinin A (PHA)-induced human peripheral blood mononuclear cell (PBMC) proliferation assay. In this screening, we isolated from Alomia myriadenia Schultz-Bip. ex.

[Anti-live Leishmania (Viannia) braziliensis promastigote antibodies, detected by flow cytometry, to identify active infection in american cutaneous leishmaniasis].

In the current study we described initial standardization steps of a new methodology to detect anti-live Leishmania (Viannia) braziliensis promastigote antibodies by flow cytometry, followed by analysis of its applicability to clinical studies. We have studied 39 individuals with positive conventional serology to leishmaniasis, classified according to the absence/presence of cutaneous lesions (L- and L+). The results were expressed as percentage of positive fluorescent parasites (PPFP).

Evidence that development of severe cardiomyopathy in human Chagas' disease is due to a Th1-specific immune response.

The role of interleukin 10 (IL-10) and gamma interferon (IFN-gamma) on the development of pathology in human Chagas' disease was investigated. Two categories of patients, low and high producers of IFN-gamma, were identified based on the levels of secretion of this cytokine in the supernatant of peripheral blood mononuclear cell (PBMC) cultures. Eighty-three percent of the patients presenting with cardiac disease (CARD) of different degrees and 59% of the patients with the indeterminate form of disease (IND) were identified as high IFN-gamma producers.

Additive host genetic factors influence fecal egg excretion rates during Schistosoma mansoni infection in a rural area in Brazil.

This study quantifies the influence of shared household and kinship on egg counts during Schistosoma mansoni infection in a sample from rural Brazil. Detailed genealogic information allowed assignment of 597 individuals to 6 multihousehold pedigrees residing in 145 households. A variance component method was used to partition egg counts into shared household, additive genetic, and individual-specific environmental effects.

Plasma concentrations and role of macrophage inflammatory protein-1alpha during chronic Schistosoma mansoni infection in humans.

Chemokines play an important role during granulomatous inflammation in murine models of Schistosoma mansoni infection. Here, the expression and possible roles of chemokines during human S. mansoni infection were examined.

Cis-acting elements, CArG-, E-, CCAAT- and TATA-boxes may be involved in sexually regulated gene transcription in Schistosoma mansoni.

Schistosomes undergo various morphological and metabolic changes during their development, reflected in a finely tuned regulation of protein and/or gene expression. The mechanisms involved in the control of gene expression during the development of the parasite are not understood. Two actin genes had been previously cloned and observed to be differentially expressed during the maturation of the parasite.

Indirect effects of oral tolerance to ovalbumin interfere with the immune responses triggered by Schistosoma mansoni eggs.

The objective of the present study was to investigate whether the injection of a tolerated protein (indirect effects) affects the formation of granulomas around Schistosoma mansoni eggs trapped in the lungs after intravenous (iv) injection into normal (noninfected) C57BL/6 mice (6 animals per group). To induce oral tolerance to chicken egg ovalbumin a 1/5 dilution of egg white in water was offered ad libitum in a drinking bottle for 3 days. Control mice received water.

Hepatitis C and hepatitis B virus infection in different hemodialysis units in Belo Horizonte, Minas Gerais, Brazil.

The prevalence, virological and epidemiological aspects of the hepatitis C virus (HCV) and the hepatitis B virus (HBV) infections vary among hemodialysis patients in different countries. Aiming at analyzing these aspects of HCV and HBV infections in hemodialysis patients in Belo Horizonte, MG, Brazil, we studied three hemodialysis units including 434 patients. Serology was used to detect anti-HCV and HBsAg.

Progressive Chagas' cardiomyopathy is associated with low selenium levels.

Selenium (Se) deficiency is linked with some cardiomyopathies. Its status was determined in 170 patients with chronic Chagas' disease from 2 Brazilian regions (Rio de Janeiro and Belo Horizonte), clinically stratified into groups as follows: indeterminate or asymptomatic (IND); cardiac asymptomatic (CARDa); cardiac symptomatic with moderate to severe heart dysfunction (CARDb); and healthy adults (HA), used for comparison. In most HA, Se levels were normal, excluding an overall Se deficiency.