title: Evaluation of Brucella abortus S19 vaccines commercialized in Brazil: immunogenicity, residual virulence and MLVA15 genotyping.
abstract: Live attenuated Brucella abortus S19 is the most effective vaccine against brucellosis in cattle. The assessment of the immunological parameters is essential to guarantee the biological quality of live anti-bacteria vaccines. The evaluation of genetic stability of live bacterial vaccines is also important in quality control. The aims of the present study were to compare (i) the immunogenicity and residual virulence, and (ii) the genotypic profile (MLVA15) of the eight S19 vaccines commercialized in Brazil to the USDA S19 reference strain. Two batches of each of the eight S19 commercial vaccines used in Brazil (A-H) were tested. They were submitted to the potency and residual virulence in vivo tests recommended by OIE and typed by the multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA) described for Brucella spp. Our results demonstrated that all S19 vaccines commercialized in Brazil would be approved by Brazilian and OIE recommendations for potency and residual virulence. Furthermore, the S19 vaccine is genetically very homogeneous, as all but two batches (from the same manufacturer) tested showed identical MLVA15 profile. The two batches with different profiles presented six repeat units in locus Bruce07, instead of the five found in all other strains, including the USDA S19 reference strain. Although presenting a slightly different profile, this vaccine was also protective, as demonstrated by the immunogenicity and residual virulence assays performed. Therefore, the commercial Brazilian S19 vaccines were in accordance to Brazilian and international standards for immunogenicity and residual virulence tests. Moreover, our results also show that MLVA could be a useful inclusion to the list of in vitro tests required by the official control authorities to be applied to the commercial S19 vaccines, as an efficient assay to guarantee the quality and stability of the vaccine strains.
authors.affiliation: Laboratório de Bacteriologia Aplicada, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Karina Leite
authors.initials: KL
authors.lastname: Miranda
authors.forename: Fernando Padilla
authors.initials: FP
authors.lastname: Poester
authors.forename: Silvia
authors.initials: S
authors.lastname: Minharro
authors.forename: Elaine Maria Seles
authors.initials: EM
authors.lastname: Dorneles
authors.forename: Ana Paula Reinato
authors.initials: AP
authors.lastname: Stynen
authors.forename: Andrey Pereira
authors.initials: AP
authors.lastname: Lage
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D002004:Brucella Vaccine / Q000009:adverse effects* / Q000235:genetics / Q000276:immunology*; D002003:Brucella abortus / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D002006:Brucellosis / Q000453:epidemiology / Q000517:prevention & control / Q000662:veterinary*; D002417:Cattle; D005260:Female; D042822:Genomic Instability; D051379:Mice; D018598:Minisatellite Repeats / Q000235:genetics / Q000276:immunology; D014613:Vaccines, Attenuated / Q000009:adverse effects / Q000235:genetics / Q000276:immunology
chemical_list: D002004:Brucella Vaccine; D014613:Vaccines, Attenuated