Publications (3)6.68 Total impact
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Article: Identification of Th1-responsive leishmanial excretory-secretory antigens (LESAs).
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ABSTRACT: The objective of this study was to evaluate the immunomodulatory role of leishmanial excretory-secretory antigens (LESAs) released by in vitro cultured protozoan parasite Leishmania donovani promastigotes. A total of seventeen excretory-secretory proteins of relative molecular weights 11, 13, 16, 18, 21, 23, 26, 29, 33, 35, 42, 51, 54, 58, 64, 70 and 80kDa were identified. The proteins were divided into five fractions (F1-F5) along with the whole LESAs, these fractions were evaluated for their potential antigenicity to induce macrophage effector functions, lymphoproliferation and cytokines production capabilities. Two fractions, F1 (11, 13 and 16kDa) and F3 (26, 29 and 33kDa), were found to be highly immunogenic as they significantly induced NADPH oxidase and SOD activities as well as NOx, TNF-α, IFN-γ and IL-12 production in stimulated RAW 264.7 macrophages. Further, these antigens also induced significant proliferation of human peripheral blood mononuclear cells along with increased production of IFN-γ and IL-12. The results strongly suggest the potential role of LESAs in the modulation of macrophage effector functions and Th1 immune response that gives a hope to develop potent vaccine for visceral leishmaniasis.Experimental Parasitology 08/2012; 132(3):355-61. · 2.12 Impact Factor -
Article: Identification of TLR inducing Th1-responsive Leishmania donovani amastigote-specific antigens.
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ABSTRACT: Leishmania is known to elicit Th2 response that causes leishmaniasis progression; on the other hand, Th1 cytokines restricts amastigote growth and disease progression. In this study, we report the potential of two leishmanial antigens (65 and 98 kDa, in combination) which enhance strong macrophage effector functions, viz., production of respiratory burst enzymes, nitric oxide, and Th1 cytokines. The identification of antigens were done by resolving the crude soluble antigens on SDS-PAGE and eluted by reverse staining method. Further, RAW264.7 macrophages were challenged with eluted antigens, and the innate immune response was observed by detecting respiratory burst enzymes, nitric oxide (NOx), TNF-α, IFN-γ, IL-12, toll-like receptors (TLRs) gene expression, and TLR-signaling proteins. These antigens increased the production of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, superoxide dismutase, NOx, TNF-α, IFN-γ, IL-12, TLR2, and p38 mitogen-activated protein kinase. These antigens also induced human peripheral blood mononuclear cells proliferation and Th1 cytokine production. This study concludes that these antigens induce innate immune response as well as have prophylactic efficacy.Molecular and Cellular Biochemistry 08/2011; 359(1-2):359-68. · 2.06 Impact Factor -
Article: NADH-oxidase, NADPH-oxidase and myeloperoxidase activity of visceral leishmaniasis patients.
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ABSTRACT: It is believed that the enhanced capability of activated macrophages to resist infection is related to the remarkable increase in the production of oxygen metabolites in response to phagocytosis. Both the production of H2O2 and the oxidation of NAD(P)H are directly dependent upon NAD(P)H-oxidase. It has been established that the respiratory burst is due to activation of NAD(P)H-oxidase localised in the plasmalemma. Myeloperoxidase is believed to be involved in augmenting the cytotoxic activity of H2O2. Low NADH-oxidase, NADPH-oxidase and myeloperoxidase activity were observed in monocytes of patients with active visceral leishmaniasis as compared with healthy controls. These results suggest that low NADH-oxidase, NADPH-oxidase and myeloperoxidase activities may account for persistence of Leishmania parasites in visceral leishmaniasis.Journal of Medical Microbiology 11/2002; 51(10):832-6. · 2.50 Impact Factor
