Friday, September 25, 2009

What's new for 'Trypanosomatids' in PubMed

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PubMed Results
Items 1 -6 of 6

1: Parasitol Res. 2009 Sep 24. [Epub ahead of print]

Cysteine proteinases from promastigotes of Leishmania (Viannia) braziliensis.

Rebello KM, Côrtes LM, Pereira BA, Pascarelli BM, Côrte-Real S, Finkelstein LC, Pinho RT, d'Avila-Levy CM, Alves CR.

Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz (IOC), FIOCRUZ, Av. Brasil 4365, Manguinhos, 21045-900, Rio de Janeiro, RJ, Brazil.

Leishmania (Viannia) braziliensis is the major causative agent of American tegumentary leishmaniasis, a disease that has a wide geographical distribution and is a severe public health problem. The cysteine proteinase B (CPB) from Leishmania spp. represents an important virulence factor. In this study, we characterized and localized cysteine proteinases in L. (V.) braziliensis promastigotes. By a combination of triton X-114 extraction, concanavalin A-affinity, and ion exchange chromatographies, we obtained an enriched fraction of hydrophobic proteins rich in mannose residues. This fraction contained two proteinases of 63 and 43 kDa, which were recognized by a CPB antiserum, and were partially sensitive to E-64 in enzymatic assays with the peptide Glu-Phe-Leu. In confocal microscopy, the CPB homologues localized in the peripheral region of the parasite. This data together with direct agglutination and flow cytometry assays suggest a surface localization of the CPB homologues. The incubation of intact promastigotes with phospholipase C reduced the number of CPB-positive cells, while anti-cross-reacting determinant and anti-CPB antisera recognized two polypeptides (63 and 43 kDa) derived from phospholipase C treatment, suggesting that some CPB isoforms may be glycosylphosphatidylinositol-anchored. Collectively, our results suggest the presence of CPB homologues in L. braziliensis surface and highlight the need for further studies on L. braziliensis cysteine proteinases, which require enrichment methods for enzymatic detection.

PMID: 19777260 [PubMed - as supplied by publisher]

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2: Clin Vaccine Immunol. 2009 Sep 23. [Epub ahead of print]

Vaccination with live Leishmania major and CpG DNA promotes IL-2 production by dermal dendritic cells and NK cell activation.

Laabs EM, Wu W, Mendez S.

James A. Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca NY, 14853.

Cutaneous leishmaniasis due to Leishmania major is an emerging, chronic parasitic disease that causes disfigurement and social stigmatization. Drug therapy is inadequate, and there is no vaccine. Inoculation of virulent parasites (leishmanization) is the only intervention that has ever provided protection because it mimics natural infection and immunity, but it was discontinued due to safety concerns (uncontrolled vaccinal lesions). In an effort to retain the benefits (immunity) while avoiding the side effects (lesions) of leishmanization, we immunized C57BL/6 mice with L. major and CpG DNA (Lm/CpG). This combination prevented lesions while inducing immunity. Also, the vaccination with live parasites and the TLR-9 agonist enhanced innate immune responses by activating dermal dendritic cells (DCs) to produce cytokines. Here we report that the Lm/CpG vaccine induced dermal DC, but not bone marrow-derived DCs, to produce IL-2. The release of this unusual DC-derived cytokine was concomitant with a peak in NK cell numbers that produced IFN-gamma, and also enhanced activation of proliferation of IFN-gamma+ CD4+ T cells. Parasite growth was controlled in Lm/CpG-vaccinated animals. This is the first demonstration on the ability of dermal DCs to produce IL-2 and on the activation of NK cells by vaccination in the context of leishmaniasis. Understanding how the Lm/CpG vaccine enhances innate immunity may provide new tools to develop vaccines against Lm, other chronic infectious diseases or other conditions such as cancer.

PMID: 19776191 [PubMed - as supplied by publisher]

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3: Int J Dermatol. 2009 Oct;48(10):1091-5.

Immunohistochemistry and polymerase chain reaction on paraffin-embedded material improve the diagnosis of cutaneous leishmaniasis in the Amazon region.

Amato VS, Tuon FF, de Andrade HF Jr, Bacha H, Pagliari C, Fernandes ER, Duarte MI, Neto VA, Zampieri RA, Floeter-Winter LM, Celeste BJ, Oliveira J, Quiroga MM, Mascheretti M, Boulos M.

Infectious and Parasitic Diseases Clinic, Parasitology (LIM 46), Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, Avenida Dr. Enéas de Carvalho, São Paulo, Brazil. valdirsa@netpoint.com.br

BACKGROUND: Recently, there has been an increase in the incidence of cutaneous leishmaniasis (CL), which represents an important health problem. This increase may be related to the epidemiologic expansion of the infective agent and the increase in tourism in tropical areas. The difficulty in clinical diagnosis, mainly in areas in which CL is not the first consideration of local physicians, has intensified efforts to describe diagnostic tests, which should be specific, sensitive, and practical. Amongst the new tests described are those including nucleic acid amplification (polymerase chain reaction, PCR) and immunohistochemistry (IHC). METHODS: In this study, we evaluated the sensitivity of a PCR based on small subunit (SSU) ribosomal DNA, in comparison with IHC using Leishmania spp. antibodies, in biopsies embedded in paraffin. RESULT: The results indicated a total sensitivity of 96% (90.9% with PCR and 68.8% with IHC), showing the possibility of using paraffin-embedded biopsies to diagnose CL. CONCLUSION: We propose the use of the two tests together as a routine protocol for diagnosis. This would require the provision of local medical services to perform molecular biology techniques and adequate Leishmania antibodies.

PMID: 19775402 [PubMed - in process]

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4: Vet Parasitol. 2009 Jul 7;163(1-2):27-32. Epub 2009 Apr 5.Click here to read LinkOut

Trypanosoma cruzi: dehydroepiandrosterone (DHEA) and immune response during the chronic phase of the experimental Chagas' disease.

Caetano LC, Santello FH, Del Vecchio Filipin M, Brazão V, Caetano LN, Toldo MP, Caldeira JC, do Prado Júnior JC.

Laboratório de Parasitologia, Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café s/n, 14040-903 Ribeirão Preto, SP, Brazil. leony@fcfrp.usp.br

Dehydroepiandrosterone (DHEA) has long been considered as a precursor for many steroid hormones. It also enhances the immune responses against a wide range of viral, bacterial, and parasitic pathogens. The aims of this work were to evaluate the influences of exogenous DHEA treatment on Wistar rats infected with the Y strain of Trypanosoma cruzi during the acute and its influence on the chronic phase of infection. Animals were subcutaneous treated with 40 mg/kg body weight/day of DHEA. DHEA treatment promoted increased lymphoproliferative responses as well as enhanced concentrations of NO and IL-12. So, we point in the direction that our results validate the utility of the use of DHEA as an alternative therapy candidate against T. cruzi.

PMID: 19446400 [PubMed - indexed for MEDLINE]

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5: Vet Parasitol. 2009 Jul 7;163(1-2):127-31. Epub 2009 Apr 15.Click here to read LinkOut

Cross-protection between Trypanosoma congolense strains of low and high virulence.

Masumu J, Marcotty T, Geerts S, Vercruysse J, Van den Bossche P.

University of Pretoria, Department of Veterinary Tropical Diseases, Onderstepoort, South Africa.

The aim of this study was to assess the existence of possible cross-protection between Trypanosoma congolense strains of low and extreme virulence circulating in the same trypanosomiasis focus. Groups of six mice were infected using one of three strains of low virulence and challenged with one of three strains of extreme virulence. A group of six mice was used as control for each strain of low and extreme virulence. The results showed that mice infected with one of the strains of extreme virulence developed high parasitaemia and a significant drop of the PCV compared to mice infected with a strain of low virulence and challenged with one of the strains of extreme virulence. With an exception of one strain of extreme virulence (strain F), the survival time of mice infected with the strains of extreme virulence was shorter compared to mice infected with strains of low virulence and subsequently challenged with a strain of extreme virulence. These results suggest that in an area where trypanosomes of various virulence profiles circulate, livestock infected with T. congolense strains of low virulence can be protected against the adverse effects of extremely virulent T. congolense strains.

PMID: 19423225 [PubMed - indexed for MEDLINE]

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6: Vet Parasitol. 2009 Jul 7;163(1-2):136-9. Epub 2009 Apr 5.Click here to read LinkOut

First report of Trypanosoma vivax infection in dairy cattle from Costa Rica.

Oliveira JB, Hernández-Gamboa J, Jiménez-Alfaro C, Zeledón R, Blandón M, Urbina A.

Escuela de Medicina Veterinaria, Universidad Nacional, APDO 86-3000, Barreal de Heredia, Heredia, Costa Rica. jaquelo@medvet.una.ac.cr

An outbreak of haemoparasitoses occurred from October 2007 to July 2008 in cattle from the district of Rio Cuarto, province of Alajuela, Costa Rica. Fifty animals of various ages out of 450 Brown Swiss were affected. The animals presented fever, severe anemia, jaundice, abortion or premature birth, loss of appetite, decrease milk production and accentuated weight loss in a short period of time. Haemoparasites were observed in the blood smears: Anaplasma marginale was present in 17 animals (60.7%); Trypanosoma vivax in nine (32.1%) and Babesia bovis in two (7.1%). Three of the animals (10.7%) had a mixed infection with T. vivax and A. marginale. After treatment, all the animals were clinically recovered and subsequent blood samplings showed no parasites. Data suggest that the outbreak might be related to a decrease in the availability and quality of the pastures due to very heavy rainfalls during the year 2007, as well as an increase in the abundance of Boophilus microplus and Stomoxys calcitrans. This is the first report of the presence of T. vivax in Costa Rica.

PMID: 19414224 [PubMed - indexed for MEDLINE]

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