Browsing by Author "Keerti Rawat"

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Comparative analysis of cellular immune responses in treated Leishmania patients and hamsters against recombinant Th1 stimulatory proteins of Leishmania donovani
(Frontiers Media S.A., 2016) Sumit Joshi; Narendra K. Yadav; Keerti Rawat; Chandra Dev P. Tripathi; Anil K. Jaiswal; Prashant Khare; Rati Tandon; Rajendra K. Baharia; Sanchita Das; Reema Gupta; Pramod K. Kushawaha; Shyam Sundar; Amogh A. Sahasrabuddhe; Anuradha Dube
Our prior studies demonstrated that cellular response of T helper 1 (Th1) type was generated by a soluble antigenic fraction (ranging from 89.9 to 97.1 kDa) of Leishmania donovani promastigote, in treated Leishmania patients as well as hamsters and showed significant prophylactic potential against experimental visceral leishmaniasis (VL). Eighteen Th1 stimulatory proteins were identified through proteomic analysis of this subfraction, out of which 15 were developed as recombinant proteins. In the present work, we have evaluated these 15 recombinant proteins simultaneously for their comparative cellular responses in treated Leishmania patients and hamsters. Six proteins viz. elongation factor-2, enolase, aldolase, triose phosphate isomerase, protein disulfide isomerase, and p45 emerged as most immunogenic as they produced a significant lymphoproliferative response, nitric oxide generation and Th1 cytokine response in PBMCs and lymphocytes of treated Leishmania patients and hamsters respectively. The results suggested that these proteins may be exploited for developing a successful poly-protein and/or poly-epitope vaccine against VL. © 2016 Joshi, Yadav, Rawat, Tripathi, Jaiswal, Khare, Tandon, Baharia, Das, Gupta, Kushawaha, Sundar, Sahasrabuddhe and Dube.
Immunogenicity and Protective Efficacy of T-Cell Epitopes Derived from Potential Th1 Stimulatory Proteins of Leishmania (Leishmania) donovani
(Frontiers Media S.A., 2019) Sumit Joshi; Narendra Kumar Yadav; Keerti Rawat; Vikash Kumar; Rafat Ali; Amogh Anant Sahasrabuddhe; Mohammad Imran Siddiqi; Wahajul Haq; Shyam Sundar; Anuradha Dube
Development of a suitable vaccine against visceral leishmaniasis (VL), a fatal parasitic disease, is considered to be vital for maintaining the success of kala-azar control programs. The fact that Leishmania-infected individuals generate life-long immunity offers a viable proposition in this direction. Our prior studies demonstrated that T-helper1 (Th1) type of cellular response was generated by six potential recombinant proteins viz. elongation factor-2 (elF-2), enolase, aldolase, triose phosphate isomerase (TPI), protein disulfide isomerase (PDI) and p45, derived from a soluble antigenic fraction (89.9-97.1 kDa) of Leishmania (Leishmania) donovani promastigote, in treated Leishmania patients and golden hamsters and showed significant prophylactic potential against experimental VL. Moreover, since, it is well-known that our immune system, in general, triggers production of specific protective immunity in response to a small number of amino acids (peptide), this led to the identification of antigenic epitopes of the above-stated proteins utilizing immunoinformatics. Out of thirty-six, three peptides-P-10 (enolase), P-14, and P-15 (TPI) elicited common significant lymphoproliferative as well as Th1-biased cytokine responses both in golden hamsters and human subjects. Further, immunization with these peptides plus BCG offered 75% prophylactic efficacy with boosted cellular immune response in golden hamsters against Leishmania challenge which is indicative of their candidature as potential vaccine candidates. Copyright © 2019 Joshi, Yadav, Rawat, Kumar, Ali, Sahasrabuddhe, Siddiqi, Haq, Sundar and Dube. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Immunological consequences of stress-related proteins-cytosolic tryparedoxin peroxidase and chaperonin TCP20-identified in splenic amastigotes of Leishmania donovani as Th1 stimulatory, in experimental visceral leishmaniasis
(Cambridge University Press, 2015) Anil Kumar Jaiswal; Prashant Khare; Sumit Joshi; Keerti Rawat; Narendra Yadav; Shyam Sundar; Anuradha Dube
In earlier studies, proteomic characterization of splenic amastigote fractions from clinical isolates of Leishmania donovani, exhibiting significant cellular responses in cured Leishmania subjects, led to the identification of cytosolic tryparedoxin peroxidase (LdcTryP) and chaperonin-TCP20 (LdTCP20) as Th1-stimulatory proteins. Both the proteins, particularly LdTCP20 for the first time, were successfully cloned, overexpressed, purified and were found to be localized in the cytosol of purified splenic amastigotes. When evaluated against lymphocytes of cured Leishmania-infected hamsters, the purified recombinant proteins (rLdcTryP and rLdTCP20) induced their proliferations as well as nitric oxide production. Similarly, these proteins also generated Th1-type cytokines (IFN-γ/IL-12) from stimulated PBMCs of cured/endemic Leishmania patients. Further, vaccination with rLdcTryP elicited noticeable delayed-type hypersensitivity response and offered considerably good prophylactic efficacy (~78% inhibition) against L. donovani challenge in hamsters, which was well supported by the increased mRNA expression of Th1 and Th2 cytokines. However, animals vaccinated with rLdTCP20 exhibited comparatively lesser prophylactic efficacy (~55%) with inferior immunological response. The results indicate the potentiality of rLdcTryP protein, between the two, as a suitable anti-leishmanial vaccine. Since, rLdTCP20 is also an important target, for optimization, further attempts towards determination of immunodominant regions for designing fusion peptides may be taken up. © Cambridge University Press 2014.
Molecular, biochemical characterization and assessment of immunogenic potential of cofactor-independent phosphoglycerate mutase against Leishmania donovani: A step towards exploring novel vaccine candidate
(Cambridge University Press, 2018) Rati Tandon; Sharat Chandra; Rajendra Kumar Baharia; Pragya Misra; Sanchita Das; Keerti Rawat; Mohammad Imran Siddiqi; Shyam Sundar; Anuradha Dube
Despite immense efforts, vaccine against visceral leishmaniasis has yet not been developed. Earlier our proteomic study revealed a novel protein, cofactor-independent phoshoglycerate mutase (LdiPGAM), an important enzyme in glucose metabolism, in T helper cells type 1 (Th1) stimulatory region of soluble Leishmania donovani antigen. In this study, LdiPGAM was biochemically and molecularly characterized and evaluated for its immunogenicity and prophylactic efficacy against L. donovani. Immunogenicity of recombinant LdiPGAM (rLdiPGAM) was initially assessed in naïve hamsters immunized with it by analysing mRNA expression of inducible nitric oxide (NO) synthase (iNOS) and other Th1/T helper cells type 2 cytokines, which revealed an upregulation of Th1 cytokines along with iNOS. Immunogenicity of rLdiPGAM was further evaluated in lymphocytes of treated Leishmania-infected hamsters and peripheral blood mononuclear cells of Leishmania patients in clinical remission by various parameters, viz. lymphoproliferation assay and NO production (hamsters and patients) and levels of various cytokines (patients). rLdiPGAM induced remarkable Lymphoproliferative response and NO production in treated Leishmania-infected hamsters as well as in patients and increase in interferon gamma (IFN-γ), interleukin-12 (IL-12p40) responses in Leishmania patients in clinical remission. Vaccination with rLdiPGAM exerted considerable prophylactic efficacy (73%) supported by increase in mRNA expression of iNOS, IFN-γ and IL-12p40 with decrease in transforming growth factor beta and interleukin-10. Above results indicate the importance of rLdiPGAM protein as a potential vaccine candidate against visceral leishmaniasis. © 2018 Cambridge University Press.