title: Immunization of mice with a novel recombinant molecular chaperon confers protection against Brucella melitensis infection.
abstract: Brucella spp. are zoonotic Gram-negative intracellular pathogens with the ability to survive and replicate in phagocytes. It has been shown that bacterial proteins expressed abundantly in this niche are stress-related proteins capable of triggering effective immune responses. BMEI1549 is a molecular chaperone designated DnaK that is expressed under stress conditions and helps to prevent formation of protein aggregates. In order to study the potential of DnaK as a prospective Brucella subunit vaccine, immunogenicity and protective efficacy of recombinant DnaK from Brucella melitensis was evaluated in BALB/c mice. The dnak gene was cloned, expressed in Escherichia coli, and the resulting recombinant protein used as subunit vaccine. DnaK-immunized mice showed a strong lymphocyte proliferative response to in vitro antigen stimulation. Although comparable levels of antigen-specific IgG2a and IgG1 were observed in immunized mice, high amounts of IFN-γ, IL-12 and IL-6, no detectable level of IL-4 and very low levels of IL-10 and IL-5 were produced by splenocytes of vaccinated mice suggesting induction of a Th1 dominant immune response by DnaK. Compared to control animals, mice vaccinated with DnaK exhibited a significant degree of protection against subsequent Brucella infection (p<0.001), albeit this protection was less than the protection conferred by Rev.1 (p<0.05). A further increase in protection was observed, when DnaK was combined with recombinant Omp31. Notably, this combination, as opposed to each component alone, induced statistically similar level of protection as induced by Rev.1 suggesting that DnaK could be viewed as a promising candidate for the development of a subunit vaccine against brucellosis.
authors.affiliation: Department of Microbiology and Immunology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Ghasemi
authors.affiliation: Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran. Electronic address: Mahjed@avicenna.ac.ir.
authors.forename: Mahmood
authors.initials: M
authors.lastname: Jeddi-Tehrani
authors.affiliation: Technische Universität München & Helmholtz Zentrum München, Munich, Germany.
authors.forename: Josef
authors.initials: J
authors.lastname: Mautner
authors.affiliation: Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Salari
authors.affiliation: Nanobiotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran; Immunology Research Center, Iran University of Medical Sciences, Tehran, Iran. Electronic address: zarnani@avicenna.ac.ir.
authors.forename: Amir-Hassan
authors.initials: AH
authors.lastname: Zarnani
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology; D002004:Brucella Vaccine / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D017347:Brucella melitensis / Q000235:genetics / Q000276:immunology*; D002006:Brucellosis / Q000276:immunology / Q000517:prevention & control*; D049109:Cell Proliferation; D003001:Cloning, Molecular; D016207:Cytokines / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006360:Heat-Shock Proteins / Q000235:genetics / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood; D008214:Lymphocytes / Q000276:immunology; D008807:Mice, Inbred BALB C; D018832:Molecular Chaperones / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D017778:Vaccines, Combined / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002004:Brucella Vaccine; D016207:Cytokines; D006360:Heat-Shock Proteins; D007074:Immunoglobulin G; D018832:Molecular Chaperones; C101108:Omp31 protein, Brucella melitensis; D011994:Recombinant Proteins; D017778:Vaccines, Combined; D022223:Vaccines, Subunit; D014614:Vaccines, Synthetic
keywords: Brucella; Molecular chaperon; Recombinant protein; Vaccine