37 research outputs found
Trans-sialidase delivered as a naked DNA vaccine elicits an immunological response similar to a Trypanosoma cruzi infection
Trypanosoma cruzi, the protozoan parasite that causes Chagas' disease, does not synthesize sialic acid, but expresses a trans-sialidase (TS) that catalyzes the transfer of sialic acid from host glycoconjugates to the parasite surface. Here, we review studies that characterize the immune response to the catalytic domain of the enzyme in humans during Chagas' disease or in mice following immunization with the TS gene. In both cases, there are antibodies that strongly inhibit the enzymatic activity and generation of interferon-g-producing T cells.Universidade Federal de São Paulo (UNIFESP)Instituto Dante Pazzanese de Cardiologia do Estado de São PauloUNIFESPSciEL
Trans-sialidase delivered as a naked DNA vaccine elicits an immunological response similar to a Trypanosoma cruzi infection
Co-Administration of a Plasmid DNA Encoding IL-15 Improves Long-Term Protection of a Genetic Vaccine against Trypanosoma cruzi
Background: Immunization of mice with the Trypanosoma cruzi trans-sialidase (TS) gene using plasmid DNA, adenoviral vector, and CpG-adjuvanted protein delivery has proven highly immunogenic and provides protection against acute lethal challenge. However, long-term protection induced by TS DNA vaccines has not been reported. the goal of the present work was to test whether the co-administration of a plasmid encoding IL-15 (pIL-15) could improve the duration of protection achieved through genetic vaccination with plasmid encoding TS (pTS) alone.Methodology: We immunized BALB/c mice with pTS in the presence or absence of pIL-15 and studied immune responses [with TS-specific IFN-gamma ELISPOT, serum IgG ELISAs, intracellular cytokine staining (IFN-gamma, TNF-alpha, and IL-2), tetramer staining, and CFSE dilution assays] and protection against lethal systemic challenge at 1 to 6 months post vaccination. Mice receiving pTS alone developed robust TS-specific IFN-gamma responses and survived a lethal challenge given within the first 3 months following immunization. the addition of pIL-15 to pTS vaccination did not significantly alter T cell responses or protection during this early post-vaccination period. However, mice vaccinated with both pTS and pIL-15 challenged 6 months post-vaccination were significantly more protected against lethal T. cruzi challenges than mice vaccinated with pTS alone (P6 months post immunization. Also, these TS-specific T cells were better able to expand after in vitro restimulation.Conclusion: Addition of pIL-15 during genetic vaccination greatly improved long-term T cell survival, memory T cell expansion, and long-term protection against the important human parasite, T. cruzi.National Institutes of HealthFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)Millennium Institute for Gene TherapySt Louis Univ, Dept Internal Med, St Louis, MO 63103 USAUniversidade Federal de São Paulo, Ctr Terapia Celular & Mol, Escola Paulista Med, São Paulo, BrazilSt Louis Univ, Dept Mol Microbiol, St Louis, MO 63103 USAUniv Fed Minas Gerais, Inst Ciencias Biol, Dept Microbiol, Belo Horizonte, MG, BrazilUniversidade Federal de São Paulo, Ctr Terapia Celular & Mol, Escola Paulista Med, São Paulo, BrazilNational Institutes of Health: RO1 AI040196CNPq: 420067/2005-1Web of Scienc
SISTEMA DI COLLEGAMENTO DI GIUNTI A SEMPLICE SOVRAPPOSIZIONE CON CALETTAMENTO AUTOMATICO
Il brevetto propone un sistema per collegare due semigiunti di grosso spessore, dotati di foro opportunamente sagomato, con calettamento automatico ed irreversibile nei riguardi delle azioni che si trasmettono l’un l’altro i semigiunti in esercizio.
Esso consta essenzialmente di una spina sagomata, ad un’estremità , a forma di calettatore, realizzato in tre segmenti uguali ed equidistanziati quanto la loro dimensione trasversale, sulla quale può scorrere, in posizione contrapposta al precedente, un secondo calettatore, anch’esso realizzato in tre segmenti uguali, ma contigui, quando viene azionato il meccanismo biella-manovella per il bloccaggio del giunto. Il sistema manovella-biella presenta un’articolazione a ginocchio, azionata da un attuatore a camma, che rende il meccanismo, quando è chiuso, irreversibile sotto i carichi di esercizio. L’attuatore, a sua volta, è contenuto in una guida che lo fa ruotare di 60°, nella fase di innesto e disinnesto della spina nel giunto, per consentire al calettatore fisso di raggiungere o lasciare le superfici coniugate del foro. Il tutto è chiuso in un carter che garantisce rigidità , protezione e guida al sistema, oltre a presentare i riscontri necessari al funzionamento del meccanismo
Immunization with a plasmid DNA containing the gene of trans-sialidase reduces Trypanosoma cruzi infection in mice
Trypanosoma cruzi, the protozoan parasite that causes Chagas' disease, does not synthesize sialic acid, but expresses a trans-sialidase that catalyses the transfer of sialic acid from host glycoconjugates to the parasite surface. Several lines of evidence suggest that this enzyme is a virulence factor implicated in the establishment of infection. Here we studied whether immunization with a plasmid DNA containing a gene encoding for rite catalytic domain of the enzyme could elicit protective immunity against T. cruzi infection in mice. We observed that immunization with this plasmid DNA generated antibody and T-cell mediated immune responses. Antibodies recognized the native enzyme and inhibited its activity in vitro. Upon challenge with bloodstream trypomastigotes, immunized animals displayed reduced parasitemia and mortality. (C) 1998 Elsevier B.V. All rights reserved.Universidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilInst Dante Pazzanese Cardiol Estado São Paulo, Lab Xenodiagnost, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilWeb of Scienc
Diagnosis of cerebral toxoplasmosis in AIDS patients in Brazil: Importance of molecular and immunological methods using peripheral blood samples
Detection of Leishmania (Leishmania) infantum RNA in fleas and ticks collected from naturally infected dogs
The occurrence of the insect vector (sand flies) with low rates of Leishmania infection, as well as autochthonous transmission in the absence of the natural vector in dogs, have been reported. These unexpected data suggest a hypothesis of other arthropods as a possible way of Leishmania transmission. The prevalence of Leishmania (Leishmania) infantum in fleas and ticks collected from dogs with canine visceral leishmaniasis (CVL), as well as parasite viability, were evaluated herein. The presence of L. (L.) infantum was assayed by PCR and ELISA in ectoparasites and biological samples from 73 dogs living in a Brazilian endemic area. As the occurrence of Leishmania DNA in ticks and fleas is expected given their blood-feeding habits, we next investigated whether parasites can remain viable inside ticks. PCR and ELISA confirmed that 83% of the dogs had CVL. Fleas and ticks (nymphs, male and female adults) were collected in 55% and 63% of the 73 dogs, respectively. Out of the 60 dogs with CVL, 80% harbored ectoparasites infected with L. (L.) infantum. The infection rates of the ectoparasites were 23% and 50% for fleas and ticks, respectively. The RNA analysis of the extract from ticks left in laboratory conditions during 7 to 10 days after removal from CVL dogs showed that parasites were alive. In addition, live parasites were also detected inside adult ticks recently molted in laboratory conditions. These findings indicate a higher infection rate of L. (L.) infantum in ticks and fleas, but they do not conclusively demonstrate whether these ticks can act as vectors of CVL, despite the fact that their rates were higher than those previously described in Lutzomyia longipalpis. The presence of viable L. (L.) infantum in ticks suggests the possible importance of dog ectoparasites in CVL dissemination.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, Brazil (FAPESP)[proc 08/00520-6]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, Brazil (FAPESP)[proc-08/57245-7