Dataset Information

Liposomal Elongation Factor-1? Triggers Effector CD4 and CD8 T Cells for Induction of Long-Lasting Protective Immunity against Visceral Leishmaniasis.

ABSTRACT: Despite advances, identification and formulation of safe and effective vaccine for long-lasting protection against leishmaniasis is still inadequate. In this study, we have identified a novel antigen, leishmanial elongation factor-1? (EF1-?), as an immunodominant component of solubilized leishmanial membrane antigens that reacts with visceral leishmaniasis (VL) sera and induces cellular proliferative and cytokine response in PBMCs of cured VL subjects. Leishmanial EF1-? is a 50 kDa antigen that plays a crucial role in pathogen survival by regulating oxidative burst in the host phagocytes. Previously, immunodominant truncated forms of EF1-? from different species of Leishmania have been reported. Formulation of the L. donovani 36?kDa truncated as well as the cloned recombinant EF1-? in cationic liposomes induce strong resistance to parasitic burden in liver and spleen of BALB/c mice through induction of DTH and a IL-10 and TGF-? suppressed mixed Th1/Th2 cytokine responses. Multiparametric analysis of splenocytes for generation of antigen-specific IFN-?, IL2, and TNF-? producing lymphocytes indicate that cationic liposome facilitates expansion of both CD4+ as well as CD8+ memory and effector T cells. Liposomal EF1-? is a novel and potent vaccine formulation against VL that imparts long-term protective responses. Moreover, the flexibility of this formulation opens up the scope to combine additional adjuvants and epitope selected antigens for use in other disease forms also.

SUBMITTER: Sabur A

PROVIDER: S-EPMC5797590 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Liposomal Elongation Factor-1α Triggers Effector CD4 and CD8 T Cells for Induction of Long-Lasting Protective Immunity against Visceral Leishmaniasis.

Sabur Abdus A Bhowmick Sudipta S Chhajer Rudra R Ejazi Sarfaraz Ahmad SA Didwania Nicky N Asad Mohammad M Bhattacharyya Anirban A Sinha Utsa U Ali Nahid N

Frontiers in immunology 20180130

Despite advances, identification and formulation of safe and effective vaccine for long-lasting protection against leishmaniasis is still inadequate. In this study, we have identified a novel antigen, leishmanial elongation factor-1α (EF1-α), as an immunodominant component of solubilized leishmanial membrane antigens that reacts with visceral leishmaniasis (VL) sera and induces cellular proliferative and cytokine response in PBMCs of cured VL subjects. Leishmanial EF1-α is a 50 kDa antigen that ...[more]

PMID: 29441060

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Project description:Visceral leishmaniasis (VL), caused by infection with the intracellular protozoan Leishmania donovani, is a chronic progressive disease with a relentlessly increasing parasite burden in the spleen, liver and bone marrow. The disease is characterized by fever, splenomegaly, cachexia, and pancytopenia, and progresses to death if not treated. Control of Leishmania infection is mediated by Th1 (IFN?-producing) CD4+ T cells, which activate macrophages to produce nitric oxide and kill intracellular parasites. However, despite expansion of CD4+ T cells and increased IFN? expression in the spleen, humans with active VL do not control the infection. We used an experimental model of chronic progressive VL in hamsters, which mimics clinical and pathological features seen in humans, to better understand the mechanisms that lead to progressive disease. Transcriptional profiling of the spleen during chronic infection revealed expression of markers of both T cell activation and inhibition. CD4+ T cells isolated from the spleen during chronic progressive VL showed mixed expression of Th1 and Th2 cytokines and chemokines, and were marginally effective in controlling infection in an ex vivo T cell-macrophage co-culture system. Splenic CD4+ T cells and macrophages from hamsters with VL showed increased expression of inhibitory receptors and their ligands, respectively. Blockade of the inhibitory receptor PD-L2 led to a significant decrease in parasite burden, revealing a pathogenic role for the PD-1 pathway in chronic VL. PD-L2 blockade was associated with a dramatic reduction in expression of host arginase 1, but no change in IFN? and inducible nitric oxide synthase. Thus, the expression of counter-regulatory molecules on splenic CD4+ T cells and macrophages promotes a more permissive macrophage phenotype and attenuates intracellular parasite control in chronic progressive VL. Host-directed adjunctive therapy targeting the PD-1 regulatory pathway may be efficacious for VL.

Project description:BackgroundThere is a continued need to develop effective and safe treatments for visceral leishmaniasis (VL). Preclinical studies on pharmacokinetics and pharmacodynamics of anti-infective agents, such as anti-bacterials and anti-fungals, have provided valuable information in the development and dosing of these agents. The aim of this study was to characterise the pharmacokinetic and pharmacodynamic properties of the anti-leishmanial drugs AmBisome and miltefosine in a preclinical disease model of VL.Methodology / principal findingsBALB/c mice were infected with L. donovani (MHOM/ET/67/HU3) amastigotes. Groups of mice were treated with miltefosine (orally, multi-dose regimen) or AmBisome (intravenously, single dose regimen) or left untreated as control groups. At set time points groups of mice were killed and plasma, livers and spleens harvested. For pharmacodynamics the hepatic parasite burden was determined microscopically from tissue impression smears. For pharmacokinetics drug concentrations were measured in plasma and whole tissue homogenates by LC-MS. Unbound drug concentrations were determined by rapid equilibrium dialysis. Doses exerting maximum anti-leishmanial effects were 40 mg/kg for AmBisome and 150 mg/kg (cumulatively) for miltefosine. AmBisome displayed a wider therapeutic range than miltefosine. Dose fractionation at a total dose of 2.5 mg/kg pointed towards concentration-dependent anti-leishmanial activity of AmBisome, favouring the administration of large doses infrequently. Protein binding was >99% for miltefosine and amphotericin B in plasma and tissue homogenates.Conclusion / significanceUsing a PK/PD approach we propose optimal dosing strategies for AmBisome. Additionally, we describe pharmacokinetic and pharmacodynamic properties of miltefosine and compare our findings in a preclinical disease model to available knowledge from studies in humans. This approach also presents a strategy for improved use of animal models in the drug development process for VL.

Dataset Information

Liposomal Elongation Factor-1? Triggers Effector CD4 and CD8 T Cells for Induction of Long-Lasting Protective Immunity against Visceral Leishmaniasis.

Publications

Liposomal Elongation Factor-1α Triggers Effector CD4 and CD8 T Cells for Induction of Long-Lasting Protective Immunity against Visceral Leishmaniasis.

Similar Datasets

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