Topic
Visceral leishmaniasis
About: Visceral leishmaniasis is a research topic. Over the lifetime, 7486 publications have been published within this topic receiving 184865 citations. The topic is also known as: Kala-Azar & viscus leishmaniasis.
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TL;DR: The recombinant A2 protein produced in Escherichia coli cells was specifically recognized by immune serum from a patient with visceral leishmaniasis and has strong homology with an S antigen of Plasmodium falciparum, the protozoan parasite responsible for malaria.
Abstract: Leishmania protozoans are the causative agents of leishmaniasis, a major parasitic disease in humans. During their life cycle, Leishmania protozoans exist as flagellated promastigotes in the sand fly vector and as nonmotile amastigotes in the mammalian hosts. The promastigote-to-amastigote transformation occurs in the phagolysosomal compartment of the macrophage cell and is a critical step for the establishment of the infection. To study this cytodifferentiation process, we differentially screened an amastigote cDNA library with life cycle stage-specific cDNA probes and isolated seven cDNAs representing amastigote-specific transcripts. Five of these were closely related (A2 series) and recognized, by Northern (RNA) blot analyses, a 3.5-kb transcript in amastigotes and in amastigote-infected macrophages. Expression of the amastigote-specific A2 gene was induced in promastigotes when they were transferred from culture medium at 26 degrees C and pH 7.4 to medium at 37 degrees C and pH 4.5, conditions which mimic the macrophage phagolysosomal environment. A2 genes are clustered in tandem arrays, and a 6-kb fragment corresponding to a unit of the cluster was cloned and partially sequenced. An open reading frame found within the A2-transcribed region potentially encoded a 22-kDa protein containing repetitive sequences. The recombinant A2 protein produced in Escherichia coli cells was specifically recognized by immune serum from a patient with visceral leishmaniasis. The A2 protein repetitive element has strong homology with an S antigen of Plasmodium falciparum, the protozoan parasite responsible for malaria. Both the A2 protein of Leishmania donovani and the S antigen of P. falciparum are stage specific and developmentally expressed in mammalian hosts.
147 citations
TL;DR: This poster discusses cutaneous and mucosal leishmaniasis, a zoonosis-causative parasites, primarily those of wild animals, and neotropical Leishmania species-as recorded in humans and resultant pathologies.
Abstract: Keywords:
New World leishmaniasis;
neotropical cutaneous leishmaniasis (NCL)-seeming to be of great antiquity;
cutaneous leishmaniasis-widespread in Latin America;
NCL, a zoonosis-causative parasites, primarily those of wild animals;
anergic diffuse cutaneous leishmaniasis (ADCL) and American visceral leishmaniasis (AVL);
neotropical Leishmania species-as recorded in humans and resultant pathologies;
Leishmania-like parasites of uncertain taxonomic position;
cutaneous and mucosal leishmaniasis
146 citations
TL;DR: The results suggest that in analogy with murine models, there is a dichotomy in the human T-cell response to L. donovani infections, where preferential activation of IL-4-producing Th2-like cells may be involved in the exacerbation of human VL, whereas activation of IFN-gamma- producing Th1 cells may protect the host from severe disease.
Abstract: Infections in humans by Leishmania donovani parasites can result in a fatal disease, visceral leishmaniasis (VL), or in a self-limiting asymptomatic infection. In murine models of the infection employing Leishmania major, the course of the disease can be directed into a VL-like syndrome by interleukin-4 (IL-4)-producing Th2 cells, or cure may result by Th1 cells secreting gamma interferon (IFN-gamma). The present study examined the potential of human T cells to generate Th1 or Th2 responses to L. donovani. The profiles of IFN-gamma, IL-4, and lymphotoxin secretion after antigen stimulation were analyzed in a panel of L. donovani-reactive CD4+ human T-cell clones generated from individuals who had recovered from VL after antimonial treatment. Two of the T-cell clones produced large amounts of IL-4 without production of IFN-gamma, seven clones produced both IFN-gamma and IL-4, and eight produced only IFN-gamma. This is the first report of a Th1- and Th2-type response in human leishmaniasis. These results suggest that in analogy with murine models, there is a dichotomy in the human T-cell response to L. donovani infections. Preferential activation of IL-4-producing Th2-like cells may be involved in the exacerbation of human VL, whereas activation of IFN-gamma-producing Th1 cells may protect the host from severe disease. Identification of leishmanial antigens activating one or the other type of T cells will be important in the development of vaccines against leishmaniasis.
146 citations
TL;DR: The effectiveness of the prime-boost strategy by immunizing dogs with a plasmid carrying the gene for the LACK antigen from Leishmania infantum followed by a booster with a rVV containing the same gene (rVV-LACK) is described to have utility against visceral leishmaniasis in dogs.
146 citations
TL;DR: In this article, a randomized clinical trial of liposomal amphotericin B in the treatment and secondary prophylaxis of HIV-VL coinfected patients is urgently needed to optimize treatment.
Abstract: Liposomal amphotericin B has been used with increasing frequency to treat visceral leishmaniasis (VL). It is the treatment of choice for immunocompetent patients in the Mediterranean region and the preferred drug for HIV/VL co-infection. Although there is a regional variation in the susceptibility of the parasite a total dose of 20 mg/kg is effective in immunocompetent patients. Randomized clinical trials of liposomal amphotericin B in the treatment and secondary prophylaxis of HIV-VL coinfected patients is urgently needed to optimize treatment in this subset. With the availability of Liposomal amphotericin B at a preferential pricing in the endemic areas, short course combination therapy can become a viable alternative.
146 citations