Leishmaniasis is transmitted between mammalian hosts by the bites of bloodsucking vector sand flies. The dose of parasites transmitted to the mammalian host has never been directly determined. We developed a real-time PCR-based method to determine the number of Leishmania major parasites inoculated into the ears of living mice during feeding by individual infected flies (Phlebotomus duboscqi). ...

The levels of regulatory T cells (Treg cells), analyzed by Foxp3 mRNA expression, were determined in lesions from patients with acute cutaneous leishmaniasis (ACL) and chronic cutaneous leishmaniasis (CCL). We demonstrated that Treg cells preferentially accumulate in lesions from ACL patients during the early phase of infection (lesion duration of less than 1 month). In addition, levels of Foxp...

In the present work we analyze the antigenicity of Leishmania major ribosomal proteins (LRP) in infected BALB/c mice. We show that BALB/c mice vaccinated with LRP in the presence of CpG oligodeoxynucleotides (CpG-ODN) were protected against the development of dermal pathology and showed a reduction in the parasite load after challenge with L. major. This protection was associated with the induc...

Pythium insidiosum immunomodulatory vaccine (PiV) has been tested in clinical and experimental pythiosis. Previous data showed that P. insidiosum immunogens have the ability to switch the Th2 immune response, normally in place during pythiosis, to a curative Th1 response. Pythiosis cannot be reproduced in experimental rodents with the exception of rabbits, and thus thorough evaluation of PiV´s ...

Background: Leishmania is a pathogenic parasite which infects mononuclear cells in vertebrate hosts. Different strategies have been taken to develop immunity against Leishmania . DCs loaded with immunogenic antigen have resulted in different levels of Th1-type immune response and cytotoxic T lymphocytes (CTL) activity. Objective: To evaluate the potency of DCs primed with soluble Leishmania mex...

The in vitro growth of promastigote cells of Leishmania amazonensis was found to strongly depend on interactions among strains that differed in their pentamidine resistance. In particular, the growth of resistant strains was reduced when they shared the same environment with a less-resistant strain.

For many infectious diseases that still don’t have an effective vaccine, enhancing T cell immune response may be the key to solve this problem. Leijuvant represents a whole new perspective of adjuvant that uses Leishmania as an effective T cell stimulator. Leishmania is a parasite that specifically lives within macrophage, a professional antigen presenting cell (APC). As a potential vaccine adj...

Leishmania infections involve an acute phase of replication within macrophages, typically associated with pathology. After recovery parasites persist for long periods, which can lead to severe disease upon reactivation. Unlike the role of host factors, parasite factors affecting persistence are poorly understood. Leishmania major lacking phosphoglycans (lpg2-) were unable to survive in sand fli...

Direct drug screening against the mammalian stage of Leishmania has been hampered by cost and the time consuming effort required to accomplish it. The ability to derive transgenic Leishmania expressing reporter genes opened up new possibilities for the development of drug screening tests. Further developments to standardize and gather multiple informations could now be envisionned. We will disc...

The metabolism of protozoan parasites of the Leishmania genus is strongly based on amino acid consumption, but little is known about amino acid uptake in these organisms. In the present work, we identified a Leishmania amazonensis gene (La-PAT1) encoding a putative amino acid transporter that belongs to the amino acid/auxin permease family, a group of H(+)/amino acid symporters. This single cop...