Infection by vector-borne protozoa of the genus Leishmania occurs by the deposition of parasites within the skin of the mammalian host, where they eventually bind to and are phagocytized by Mphis. Our previous work supported the idea that parasites can interact with extracellular matrix and basement membrane proteins, such as fibronectin (FN), within the skin, leading to enhanced invasion. In t...

BACKGROUND Leishmaniases are a group of diseases caused by Leishmania parasites. Growing of drug unresponsiveness in leishmaniasis patients necessitates the development of new drugs and accordingly a suitable assay is needed for evaluation of any modalities. The aim of this study was to compare four drug assays methods, agar dilution, broth dilution, cylinder plate and disk diffusion, for evalu...

Epidermal Langerhans cells (LC) are immature dendritic cells (DC) located in close proximity to the site of inoculation of infectious Leishmania major metacyclic promastigotes by sand flies. Using LC-like DC expanded from C57BL/6 fetal skin, we characterized interactions involving several developmental stages of Leishmania and DC. We confirmed that L. major amastigotes, but not promastigotes, e...

BACKGROUND: Leishmania is an intracellular parasite of monocytes transmissible by transfusion. The feasibility of reducing Leishmania with leukodepletion filters was studied. At collection, infected blood contains the amastigote form of Leishmania within monocytes. Amastigotes cause the rupture of monocytes releasing free amastigotes that convert to promastigotes which exist extracellularly at ...

Human leishmaniasis covers a broad spectrum of clinical manifestations ranging from self-healing cutaneous leishmaniasis to severe and lethal visceral leishmaniasis caused among other species by Leishmania major or Leishmania donovani, respectively. Some drug candidates are in clinical trials to substitute current therapies, which are facing emerging drug-resistance accompanied with serious sid...

Gene expression profiling is increasingly used in the field of infectious diseases for characterization of host, pathogen and the nature of their interaction. The purpose of this study was to develop a robust, standardized method for comparative expression profiling and molecular characterization of Leishmania donovani clinical isolates. The limitations and possibilities associated with express...

It was recently hypothesized that Leishmania amastigotes could constitute a semi-quiescent stage characterized by low replication and reduced metabolic activity. This concept developed with Leishmania (Leishmania) mexicana and Leishmania (Leishmania) major models might explain numerous clinical and sub-clinical features of Leishmania (Viannia) braziliensis infections, like reactivation of the d...

Proliferation of Leishmania mexicana promastigotes in synthetic medium can be blocked by the depletion of intracellular polyamine pools induced by the presence of D,L-alpha-difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase (ODC). Here we report that DFMO-resistant cell lines growing normally at DFMO levels of 10 mM have been obtained from non-proli...

During Leishmania major infection in mice, gamma interferon (IFN-gamma) plays an essential role in controlling parasite growth and disease progression. In studies designed to ascertain the role of IFN-gamma in Leishmania amazonensis infection, we were surprised to find that IFN-gamma could promote L. amazonensis amastigote replication in macrophages (Mphis), although it activated Mphis to kill ...

Leishmania protozoa must adapt rapidly to widely different environments and thus exist as promastigotes in their sandfly host and as amastigotes in their mammalian host. Promastigote differentiation into amastigotes is accompanied by both morphological and biological changes. The molecular mechanisms regulating the differentiation and survival of the different life cycle stages are poorly under...