title: A prime-boost strategy using the novel vaccine candidate, LemA, protects hamsters against leptospirosis.
abstract: Toward developing an effective vaccine capable of conferring heterologous protection, the putative lipoprotein LemA, which presents an M3 epitope similar to that of Listeria, was evaluated as a vaccine candidate in the hamster model of leptospirosis. LemA is conserved (>70% pairwise identity) among the pathogenic Leptospira spp., indicating its potential in stimulating a cross-protective immune response. Using different vaccination strategies, including prime-boost, DNA vaccine, and a subunit preparation, recombinant LemA conferred different levels of protection in hamsters. Significant protection against mortality was observed for the prime-boost and the DNA vaccine strategies, which showed 87.5% (P < 0.01) and 62.5% (P < 0.05) efficacy, respectively. Although the subunit vaccine preparation protected 50.0% of immunized hamsters, the level of protection was not significant. None of the hamsters in the control groups survived challenge with a virulent strain of Leptospira interrogans serogroup Icterohaemorrhagiae. Characterization of the immune response found that the strongest antibody response was stimulated by the subunit vaccine preparation, followed by the prime-boost strategy. The DNA vaccine failed to elicit an antibody response in immunized hamsters.
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, Pelotas, RS, Brazil.
authors.forename: Daiane D
authors.initials: DD
authors.lastname: Hartwig
authors.forename: Karine M
authors.initials: KM
authors.lastname: Forster
authors.forename: Thaís L
authors.initials: TL
authors.lastname: Oliveira
authors.forename: Marta
authors.initials: M
authors.lastname: Amaral
authors.forename: Alan J A
authors.initials: AJ
authors.lastname: McBride
authors.forename: Odir A
authors.initials: OA
authors.lastname: Dellagostin
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000008:administration & dosage / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology*; D006224:Cricetinae; D004195:Disease Models, Animal; D007117:Immunization, Secondary; D041383:Leptospira interrogans serovar icterohaemorrhagiae / Q000276:immunology*; D007922:Leptospirosis / Q000276:immunology* / Q000517:prevention & control; D014157:Transcription Factors / Q000008:administration & dosage / Q000276:immunology*; D014611:Vaccination; D019444:Vaccines, DNA / Q000276:immunology; D022223:Vaccines, Subunit / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D014157:Transcription Factors; D019444:Vaccines, DNA; D022223:Vaccines, Subunit; D014614:Vaccines, Synthetic; C074165:lemA protein, bacterial