title: Th1 stimulatory proteins of Leishmania donovani: comparative cellular and protective responses of rTriose phosphate isomerase, rProtein disulfide isomerase and rElongation factor-2 in combination with rHSP70 against visceral leishmaniasis.
abstract: In visceral leishmaniasis, the recovery from the disease is always associated with the generation of Th1-type of cellular responses. Based on this, we have previously identified several Th1-stimulatory proteins of Leishmania donovani -triose phosphate isomerase (TPI), protein disulfide isomerase (PDI) and elongation factor-2 (EL-2) etc. including heat shock protein 70 (HSP70) which induced Th1-type of cellular responses in both cured Leishmania patients/hamsters. Since, HSPs, being the logical targets for vaccines aimed at augmenting cellular immunity and can be early targets in the immune response against intracellular pathogens; they could be exploited as vaccine/adjuvant to induce long-term immunity more effectively. Therefore, in this study, we checked whether HSP70 can further enhance the immunogenicity and protective responses of the above said Th1-stimulatory proteins. Since, in most of the studies, immunogenicity of HSP70 of L. donovani was assessed in native condition, herein we generated recombinant HSP70 and tested its potential to stimulate immune responses in lymphocytes of cured Leishmania infected hamsters as well as in the peripheral blood mononuclear cells (PBMCs) of cured patients of VL either individually or in combination with above mentioned recombinant proteins. rLdHSP70 alone elicited strong cellular responses along with remarkable up-regulation of IFN-γ and IL-12 cytokines and extremely lower level of IL-4 and IL-10. Among the various combinations, rLdHSP70 + rLdPDI emerged as superior one augmenting improved cellular responses followed by rLdHSP70 + rLdEL-2. These combinations were further evaluated for its protective potential wherein rLdHSP70 + rLdPDI again conferred utmost protection (∼80%) followed by rLdHSP70 + rLdEL-2 (∼75%) and generated a strong cellular immune response with significant increase in the levels of iNOS transcript as well as IFN-γ and IL-12 cytokines which was further supported by the high level of IgG2 antibody in vaccinated animals. These observations indicated that vaccine(s) based on combination of HSP70 with Th1-stimulatory protein(s) may be a viable proposition against intracellular pathogens.
authors.affiliation: Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Jaiswal
authors.affiliation: Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Prashant
authors.initials: P
authors.lastname: Khare
authors.affiliation: Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Sumit
authors.initials: S
authors.lastname: Joshi
authors.affiliation: Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Pramod Kumar
authors.initials: PK
authors.lastname: Kushawaha
authors.affiliation: Department of Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
authors.forename: Shyam
authors.initials: S
authors.lastname: Sundar
authors.affiliation: Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Dube
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006224:Cricetinae; D005260:Female; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D007111:Immunity, Cellular / Q000187:drug effects; D007114:Immunization; D007893:Leishmania donovani / Q000276:immunology; D054332:Leishmaniasis Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000276:immunology / Q000401:mortality / Q000469:parasitology / Q000517:prevention & control*; D008297:Male; D020652:Peptide Elongation Factor 2 / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D019704:Protein Disulfide-Isomerases / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D015800:Protozoan Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D016019:Survival Analysis; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology / Q000469:parasitology; D014305:Triose-Phosphate Isomerase / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D018840:HSP70 Heat-Shock Proteins; D054332:Leishmaniasis Vaccines; D020652:Peptide Elongation Factor 2; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D014305:Triose-Phosphate Isomerase; D019704:Protein Disulfide-Isomerases