title: Immunogenicity of a DNA and Recombinant Protein Vaccine Combining LipL32 and Loa22 for Leptospirosis Using Chitosan as a Delivery System.
abstract: Leptospirosis is a worldwide zoonotic disease caused by pathogenic Leptospira, a genus of which more than 250 serovars have been identified. Commercial bacterin vaccines are limited in that they lack both cross-protection against heterologous serovars and long-term protection. This study investigated in mice the immunogenicity of an anti-leptospirosis vaccine, using the outer membrane proteins LipL32 and Loa22 as antigens. The immunogenicity of this vaccine formulation was compared with those induced by vaccines based on LipL32 or Loa22 alone. A DNA-encapsulated chitosan nanoparticle was used for in vivo DNA delivery. Using a unique DNA plasmid expressing both lipL32 and loa22 for vaccination, higher antibody responses were induced than when combining plasmids harboring each gene separately. Therefore, this formulation was used to test the immunogenicity when administered by a heterologous prime (DNA)-boost (protein) immunization regimen. The specific antibody responses against LipL32 (total IgG and IgG1) and Loa22 (IgG1) were higher in mice receiving two antigens in combination than in those vaccinated with a single antigen alone. Although no significant difference in splenic CD4+ T cell proliferation was observed among all groups of vaccinated mice, splenocytes from mice vaccinated with two antigens exhibited higher interferon-γ and IL-2 production than when using single antigens alone upon in vitro restimulation. Taken together, the immunogenicity induced by LipL32 and Loa22 antigens in a heterologous primeboost immunization regimen using chitosan as a DNA delivery system induces higher immune response, and may be useful for developing a better vaccine for leptospirosis.
authors.affiliation: Interdisciplinary Program in Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Supawadee
authors.initials: S
authors.lastname: Umthong
authors.affiliation: Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.|Chulalongkorn University Vaccine Research Center, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Arun
authors.initials: A
authors.lastname: Buaklin
authors.affiliation: Chulalongkorn University Vaccine Research Center, Chulalongkorn University, Bangkok 10330, Thailand.|Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Alain
authors.initials: A
authors.lastname: Jacquet
authors.affiliation: Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand.
authors.forename: Noppadol
authors.initials: N
authors.lastname: Sangjun
authors.affiliation: Interdisciplinary Program in Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Ruthairat
authors.initials: R
authors.lastname: Kerdkaew
authors.affiliation: Interdisciplinary Program in Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand.|Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.|Chulalongkorn University Vaccine Research Center, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Kanitha
authors.initials: K
authors.lastname: Patarakul
authors.affiliation: Interdisciplinary Program in Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand.|Chulalongkorn University Vaccine Research Center, Chulalongkorn University, Bangkok 10330, Thailand.|Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Tanapat
authors.initials: T
authors.lastname: Palaga
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000276:immunology*; D001426:Bacterial Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000276:immunology*; D002460:Cell Line; D048271:Chitosan / Q000737:chemistry; D016207:Cytokines / Q000097:blood; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D007114:Immunization; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007919:Leptospira / Q000276:immunology*; D007922:Leptospirosis / Q000517:prevention & control*; D008074:Lipoproteins / Q000008:administration & dosage / Q000737:chemistry / Q000276:immunology*; D051379:Mice; D053758:Nanoparticles / Q000008:administration & dosage / Q000737:chemistry; D011994:Recombinant Proteins; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D014611:Vaccination; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D016207:Cytokines; D007074:Immunoglobulin G; C406589:LipL32 protein, Leptospira; D008074:Lipoproteins; D011994:Recombinant Proteins; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic; D048271:Chitosan