title: Efficacy of Leishmania donovani trypanothione reductase, identified as a potent Th1 stimulatory protein, for its immunogenicity and prophylactic potential against experimental visceral leishmaniasis.
abstract: In visceral leishmaniasis (VL), Th1-type of immune responses play an important role which correlates with recovery from and resistance to disease resulting in lifelong immunity. Based on this rationale, the soluble leishmanial antigens that elicit cellular responses in peripheral blood mononuclear cells (PBMCs) from cured Leishmania patients were characterized through immunoproteomic approach which led to the identification of trypanothione reductase (TPR) (a cytosolic enzyme explored as a drug target), as one of the potent Th1 stimulatory protein. In this study, the immunogenicity of recombinant Leishmania donovani TPR (rLdTPR) was assessed in PBMCs of cured Leishmania-infected patients/hamsters and further evaluated its prophylactic efficacy against L. donovani challenges in hamsters. Substantial proliferative responses to rLdTPR, as compared to soluble L. donovani antigen, were observed in Leishmania-infected cured patients as well as in hamsters. Moreover, rLdTPR reasonably stimulated PBMCs of cured Leishmania patients to produce IFNγ, IL-12, and TNF-α but not IL-4 or IL-10. On the other hand, the protein downregulated LPS-induced IL-10 as well as soluble L. donovani antigen-induced IL-4 production in PBMCs of Leishmania patients. In case of cured hamsters, rLdTPR generates mixed Th1 and Th2 immune response. Vaccination with rLdTPR along with Bacillus Calmette-Guerin (BCG) was able to provide considerably good prophylactic efficacy (~60%) against L. donovani challenge in hamsters. The efficacy was supported by the increased inducible NO synthase mRNA transcript and Th1-type cytokines IFNγ, IL-12, and TNF-α and downregulation of IL-4, IL-10, and TGF-β. Since rLdTPR protein is an important target, further attempts towards determination of immunodominant regions for designing fusion peptides may be taken up to optimize its prophylactic efficacy.
authors.affiliation: Division of Parasitology, Central Drug Research Institute (CDRI), Post Box No. 173, Lucknow, 226 001, India.
authors.forename: Prashant
authors.initials: P
authors.lastname: Khare
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Jaiswal
authors.forename: Chandra Dev Pati
authors.initials: CD
authors.lastname: Tripathi
authors.forename: Sumit
authors.initials: S
authors.lastname: Joshi
authors.forename: Shyam
authors.initials: S
authors.lastname: Sundar
authors.forename: Anuradha
authors.initials: A
authors.lastname: Dube
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000917:Antibody Formation; D000953:Antigens, Protozoan / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D006224:Cricetinae; D016207:Cytokines / Q000276:immunology; D005260:Female; D006801:Humans; D007223:Infant; D007893:Leishmania donovani / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D007898:Leishmaniasis, Visceral / Q000276:immunology / Q000517:prevention & control*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009247:NADH, NADPH Oxidoreductases / Q000276:immunology*; D016052:Protozoan Vaccines / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology*; D014611:Vaccination; D055815:Young Adult
chemical_list: D000953:Antigens, Protozoan; D016207:Cytokines; D016052:Protozoan Vaccines; D011994:Recombinant Proteins; D009247:NADH, NADPH Oxidoreductases; C049608:trypanothione reductase