Lymphocytes influence Leishmania major pathogenesis in a strain-dependent manner

by Md. Abu Musa, Risa Nakamura, Asma Hena, Sanjay Varikuti, Hira L. Nakhasi, Yasuyuki Goto, Abhay Satoskar, Shinjiro Hamano Cutaneous leishmaniasis (CL) is the most common form of leishmaniasis and is caused by several species ofLeishmania parasite. Clinical presentation of CL varies from a self-healing infection to a chronic form of the disease determined by the virulence of infectingLeishmania species and host immune responses to the parasite. Mouse models of CL show contradictory roles of lymphocytes in pathogenesis, while acquired immune responses are responsible for host protection from diseases. To reconcile the inconclusive roles of acquired immune responses in pathogenesis, we infected mice from various genetic backgrounds with two pathogenic strains ofLeishmania major, Friedlin or 5ASKH, and assessed the outcome of the infections. Our findings showed that the genetic backgrounds ofL.major determine the impact of lymphocytes for pathogenesis. In the absence of lymphocytes,L.major Friedlin induced the lowest inflammatory reaction and pathology at the site of infection, while 5ASKH infection induced a strong inflammatory reaction and severe pathology. Lymphocytes ameliorated 5ASKH mediated pathology, while it exacerbated pathology during Friedlin infection. Excess inflammatory reactions, like the recruitment of macrophages, neutrophils, eosinophils and production of pro-inflammatory cytokines, together with uncontrolled parasite growth in the absence of lymphocytes dur...
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research

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Conclusion: Leishmania major is responsible for the most common CL in southern Iran. In addition, in two patients with L. major and L. tropica, mix infection with Crithidia was confirmed. The potential role of Crithidia as the main factor for CL and the probability of this parasite to have synergistic effects on Leishmania, as a hypothesis, requires more comprehensive researches on the ambiguity of this protozoon. PMID: 31803781 [PubMed]
Source: Iranian Journal of Arthropod-Borne Diseases - Category: Infectious Diseases Tags: J Arthropod Borne Dis Source Type: research
Leishmaniases are widespread neglected diseases with an incidence of 1.6 million new cases and 40 thousand deaths per year. Leishmania parasites may show distinct, species-specific patterns of virulence that lead to different clinical manifestations. It is well known that successive in vitro passages (SIVP) lead to the attenuation of virulence, but neither the metabolism nor the pathways involved in these processes are well understood. Herein, promastigotes of a virulent L. amazonensis strain recently isolated from mice was compared to SIVP derived and attenuated promastigotes, submitted to 10, 40, and 60 axenic passages a...
Source: Frontiers in cellular and infection microbiology - Category: Microbiology Source Type: research
This study indicates the potential of the essential oil of O. onites and its constituents in the treatment of protozoal infections.
Source: Molecules - Category: Chemistry Authors: Tags: Article Source Type: research
AbstractCutaneous leishmaniasis (CL) is a neglected disease that promotes destructive lesions. Difficulties in treatment are related to accessibility of drugs, resistance and toxicity. Antimicrobial photodynamic therapy (APDT) has been emerging as a promising treatment for CL. In this work, we evaluated methylene blue (MB) ‐mediated APDT (MB‐APDT) onLeishmania amazonensis in vitro andin vivo by bioluminescence technique.In vitro, MB ‐APDT was performed using a red LED (λ= 660±11 nm, 100 mW/cm2) and MB (100 µM) at different light doses.In vivo, mice were infected and 4 weeks later, randomly divided...
Source: Photochemistry and Photobiology - Category: Science Authors: Tags: SPECIAL ISSUE RESEARCH ARTICLE Source Type: research
This study reported the function of the unknown proteins ofL. donovani which is imperative information for this parasite. They could be an important and promising target for new drug discovery vaccine candidate development. Further characterization and in-depth study of these unknown proteins may open a gate for successful therapy of fatal VL.
Source: Network Modeling Analysis in Health Informatics and Bioinformatics - Category: Bioinformatics Source Type: research
We present a CVL case involving a 2-year-old male dog with a history of lack of appetite, general weakness, and progressive loss of weight. A diagnosis of CVL was obtained using the direct parasitological examination in spleen and bone marrow samples stained with Giemsa. The infecting Leishmania species was identified as L. infantum by PCR-restriction fragment length polymorphism amplifying the Hsp70 gene from bone marrow and spleen samples. The patient responded favorably to treatment with intramuscular meglumine antimoniate at a dose of 100 mg/kg daily for 8 weeks and oral allopurinol at a dose of 10 mg/kg every 12 hours...
Source: Am J Trop Med Hyg - Category: Infectious Diseases Authors: Tags: Am J Trop Med Hyg Source Type: research
by Sarah Hendrickx, Lieselotte Van Bockstal, Guy Caljon, Louis Maes Monitoring the drug susceptibility ofLeishmania isolates still largely relies on standardin vitro cell-based susceptibility assays using (patient-isolated) promastigotes for infection. Although this assay is widely used, no fully standardized/harmonized protocol is yet available hence resulting in the application of a wide variety of host cells (primary cells and cell lines), different drug exposure times, detection methods and endpoint criteria. Advocacy for standardization to decrease inter-laboratory variation and improve interpretation of results has ...
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research
In this study, we describe a novel, unexplored phenomenon of a potential causal contribution of PZMs in autoreactive T cells in T1D pathogenesis. We expect that exploration of point mutations and studies in human T cells will enable the further delineation of driver genes to target for functional studies. Our findings challenge the classical notions of autoimmunity and open conceptual avenues toward individualized prevention and therapeutics.
Source: Genome Research - Category: Genetics & Stem Cells Authors: Tags: RESEARCH Source Type: research
Abstract By employing protected human bait landing and modified Shannon light trap, a total of 1,924 phlebotomine sand fly Lutzomyia spp. were captured in an area from which L. (V.) guyanensis was reported as the causative parasite of cutaneous leishmaniasis (CL). The sand flies captured alive were dissected and identified at species level, based mainly on their spermathecae. At the same time, the sand flies dissected were searched for the Leishmania parasites by microscopic-test, and later on by PCR-test. No positive sand flies were detected by both tests, while considerable numbers of anthropophilic sand fly spe...
Source: Acta Tropica - Category: Infectious Diseases Authors: Tags: Acta Trop Source Type: research
In this study, we focused on the activation of artemisinin (Art) in Leishmania tarentolae promastigotes (LtP) in comparison to reference compounds. Viability assays in different media in the presence of different iron sources (hemin/fetal calf serum) showed that IC50 values of Art in LtP were modulated by assay conditions, but overall were within the low micromolar range. Low temperature electron paramagnetic resonance (EPR) spectroscopy of LtP showed that Art shifted the redox state of the labile iron pool less than the EP ascaridole questioning its role as a major activator of Art in LtP. Based on the high reactivity of ...
Source: Biochemical Pharmacology - Category: Drugs & Pharmacology Authors: Tags: Biochem Pharmacol Source Type: research
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