Hemophagocytosis induced by Leishmania donovani  infection is beneficial to parasite survival within macrophages

by Ayako Morimoto, Kazuyuki Uchida, James K. Chambers, Kai Sato, Jing Hong, Chizu Sanjoba, Yoshitsugu Matsumoto, Junya Yamagishi, Yasuyuki Goto Visceral leishmaniasis (VL) is caused by parasitic protozoa of the genusLeishmania and is characterized by clinical manifestations such as fever, hepatosplenomegaly and anemia. Hemophagocytosis, the phenomenon of phagocytosis of blood cells by macrophages, is found in VL patients. In a previous study we established an experimental model of VL, reproducing anemia in mice for the first time, and identified hemophagocytosis by heavily infected macrophages in the spleen as a possible cause of anemia. However, the mechanism for parasite-induced hemophagocytosis or its role in parasite survival remained unclear. Here, we established anin vitro model ofLeishmania-induced hemophagocytosis to explore the molecules involved in this process. In contrast to na ïve RAW264.7 cells (mouse macrophage cell line) which did not uptake freshly isolated erythrocytes, RAW264.7 cells infected withL.donovani showed enhanced phagocytosis of erythrocytes. Additionally, for hemophagocytes found bothin vitro andin vivo, the expression of signal regulatory protein α (SIRPα), one of the receptors responsible for the ‘don’t-eat-me’ signal was suppressed by post-transcriptional control. Furthermore, the overlapped phagocytosis of erythrocytes andLeishmania parasites within a given macrophage appeared to be beneficial to the parasi...
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research

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ConclusionThe association of different techniques can detect asymptomatic infections, however, more research is necessary to develop ideal biomarkers that are simple to use in the clinic and in field studies in areas endemic for Visceral Leishmaniasis.
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research
Conclusions Nucleoside hydrolases are vital enzymes for the replication of Leishmania, conserved phylogenetic marker of the genus and strong-specific immunogens. We demonstrated that NH36 is an excellent target for chemotherapy of visceral leishmaniasis. Searching for the most immunogenic fraction of promastigotes of Leishmania we described the FML antigen of L. (L.) donovani, that has as its main component, the NH36 Nucleoside hydrolase. We developed second–generation vaccines with the FML and the NH36 native antigens, and with the NH36 recombinant protein. In addition, we obtained a third generation vaccine based ...
Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
In conclusion, we hope that this review brings about a new and more in-depth understanding of the part that Leishmania exosomes and various infectious agents play in the context of host-parasite interactions, with a particular focus on the establishment of infection. Future research in this field of investigations is critical for the development of new vaccine and diagnostic tools. Author Contributions The first draft was done by MO. AF and GD added new information. Funding Research in MO laboratory is supported by the Canadian Institute of Health Research (grant number: PJT-159765) and the Natural Sciences and Enginee...
Source: Frontiers in cellular and infection microbiology - Category: Microbiology Source Type: research
Conclusions: VL still affects children in our area. Fever, splenomegaly, anemia and appetite loss are the typical findings in children. Noninvasive techniques (immunofluorescent antibody test, rK39) in combination with bone marrow microscopy are useful in the diagnosis of pediatric VL.
Source: The Pediatric Infectious Disease Journal - Category: Infectious Diseases Tags: Original Studies Source Type: research
CONCLUSION: Visceral leishmaniasis is recognized as an emerging health threat in Sri Lanka. At least a proportion of locally identified strains of L. donovani possess the ability to visceralize. Apparent anti leishmanial sensitivity is encouraging. Timely efforts in disease containment will be important in which accurate understanding of transmission characteristics, increased professional and community awareness, improved diagnostics and availability of appropriate treatment regimens. PMID: 28820339 [PubMed - as supplied by publisher]
Source: Pathogens and Global Health - Category: International Medicine & Public Health Tags: Pathog Glob Health Source Type: research
Conclusions. VL due to L. infantum could determine periodical outbreaks, as the one described; thus it is important to include VL in the differential diagnosis of fever of unknown origin, even in low-endemic areas. PMID: 27999807 [PubMed - in process]
Source: Biomed Res - Category: Research Authors: Tags: Biomed Res Int Source Type: research
Abstract Although several reviews on canine leishmaniasis have been published, none thoroughly described clinicopathologic abnormalities and their clinical usefulness. The aim of this review was to provide information concerning current diagnostic tests relevant for clinical pathologists and from a practical perspective. Specifically, in canine leishmaniasis, nonregenerative normocytic normochromic anemia, thrombocytopenia, or leukogram changes may be present. Clinical chemistry and urinalysis may indicate renal dysfunction (azotemia, decreased urine specific gravity, proteinuria) and an inflammatory/immune response (incre...
Source: Veterinary Clinical Pathology - Category: Veterinary Research Authors: Tags: Invited Review Source Type: research
Publication date: Available online 22 September 2016 Source:International Journal for Parasitology: Parasites and Wildlife Author(s): Julia Angélica Gonçalves Silveira, Mirella Lauria D'Elia, Isabela de Oliveira Avelar, Lara Ribeiro de Almeida, Hudson Andrade dos Santos, Danielle Ferreira de Magalhães Soares, Múcio Flávio Barbosa Ribeiro, Walter dos Santos Lima, Roselene Ecco An adult free-ranged female maned wolf was rescued from a periurban area subject to anthropogenic disturbances in the Minas Gerais, Brazil. The animal presented poor body condition and anemia. The clinical condition...
Source: International Journal for Parasitology: Parasites and Wildlife - Category: Parasitology Source Type: research
Publication date: Available online 24 August 2016 Source:Preventive Veterinary Medicine Author(s): R.B.P. Torrecilha, Y.T. Utsunomiya, A.M. Bosco, B.F. Almeida, P.P. Pereira, L.G. Narciso, D.C.M. Pereira, L. Baptistiolli, L. Calvo-Bado, O. Courtenay, C.M. Nunes, P.C. Ciarlini Intensity of peripheral parasite infection has an important role in the transmission of Leishmania spp. from one host to another. As parasite load quantification is still an expensive procedure to be used routinely in epidemiological surveillance, the use of surrogate predictors may be an important asset in the identification of dogs with high transm...
Source: Preventive Veterinary Medicine - Category: Veterinary Research Source Type: research
Abstract Parasitological methods for the diagnosis of visceral leishmaniasis (VL) require invasive sampling procedures. The aim of this study was to detect Leishmania infantum (L. infantum) DNA by real time-PCR method in peripheral blood of symptomatic VL patient and compared its performance with nested PCR, an established molecular method with very high diagnostic indices. 47 parasitologically confirmed VL patients diagnosed by direct agglutination test (DAT > 3200), bone marrow aspiration and presented characteristic clinical features (fever, hepatosplenomegaly, and anemia) and 40 controls (non-end...
Source: Journal of Parasitic Diseases - Category: Parasitology Source Type: research
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