title: Protective efficacy of a DNA vaccine construct encoding the VP2 gene of infectious bursal disease and a truncated HSP70 of Mycobacterium tuberculosis in chickens.
abstract: Infectious bursal disease (IBD) is an acute, infectious, immunosuppressive disease affecting young chicken worldwide. The etiological agent IBD virus (IBDV) is a double stranded RNA virus with outer capsid protein VP2 of IBDV is the major antigenic determinant capable of inducing neutralizing antibody. DNA vaccines encoding VP2 has been extensively studied achieving only partial protection. However, the efficacy of DNA vaccines against IBDV can be augmented by choosing a potential molecular adjuvant. The goal of the present study is to evaluate the immune response and protective efficacy of a DNA vaccine encoding the C-terminal domain of the heat shock protein 70 (cHSP70) of Mycobacterium tuberculosis gene genetically fused with the full length VP2 gene of IBDV (pCIVP2-cHSP70) in comparison to a 'DNA prime-protein boost' approach and a DNA vaccine encoding the VP2 gene (pCIVP2) alone. The results indicate that both pCIVP2-cHSP70 and 'DNA prime-protein boost' elicited humoral as well as cellular immune responses. Chickens in the pCIVP2-cHSP70 and 'DNA prime-protein boost' groups developed significantly higher levels of ELISA titer to IBDV antigen compared to the group immunized with pCIVP2 alone (p<0.01). However, significantly higher levels of lymphocyte proliferative response, IL-12 and IFN-γ production were found in the pCIVP2-cHSP70 group compared to 'DNA prime-protein boost' group. Additionally, chickens immunized with pCIVP2-cHSP70 and 'DNA prime-protein boost' vaccines were completely protected against the vvIBDV whereas pCIVP2 DNA vaccine alone was able to protect only 70%. These findings suggest that the truncated C-terminal HSP70 mediated DNA vaccine genetically fused with the VP2 gene construct stimulated both humoral and cell mediated immune responses and conferred complete protection against IBDV. This novel strategy is perhaps a seminal concept in utilizing HSP70 as an adjuvant molecule to elicit an immune response against IBD affecting chickens.
authors.affiliation: Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, India.
authors.forename: Hemanta Kumar
authors.initials: HK
authors.lastname: Maity
authors.affiliation: Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, India. Electronic address: sohinimadhan@yahoo.com.
authors.forename: Sohini
authors.initials: S
authors.lastname: Dey
authors.affiliation: Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, India.
authors.forename: C Madhan
authors.initials: CM
authors.lastname: Mohan
authors.affiliation: Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, India.
authors.forename: Sagar A
authors.initials: SA
authors.lastname: Khulape
authors.affiliation: Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, India.
authors.forename: Dinesh C
authors.initials: DC
authors.lastname: Pathak
authors.affiliation: Department of Marine Biotechnology, University of Maryland, Baltimore County, 701, East Pratt Street, Baltimore, MD 21202, USA.
authors.forename: Vikram N
authors.initials: VN
authors.lastname: Vakharia
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D018175:Birnaviridae Infections / Q000662:veterinary*; D002460:Cell Line; D002645:Chickens; D016207:Cytokines / Q000378:metabolism; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000276:immunology*; D056724:Immunity, Humoral / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D011201:Poultry Diseases / Q000276:immunology / Q000378:metabolism / Q000517:prevention & control*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology*; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*; D015678:Viral Structural Proteins / Q000235:genetics / Q000276:immunology*
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D018840:HSP70 Heat-Shock Proteins; C444642:HSP70 protein, Mycobacterium tuberculosis; D011993:Recombinant Fusion Proteins; C082513:VP2 protein, infectious bursal disease virus; D019444:Vaccines, DNA; D015678:Viral Structural Proteins
keywords: Adjuvant; Complete protection; DNA vaccine; Infectious bursal disease; cHSP70