title: Mutant Brucella abortus membrane fusogenic protein induces protection against challenge infection in mice.
abstract: Brucella species can cause brucellosis, a zoonotic disease that causes serious livestock economic losses and represents a public health threat. The mechanism of virulence of Brucella spp. is not yet fully understood. Therefore, it is crucial to identify new molecules that serve as virulence factors to better understand this host-pathogen interplay. Here, we evaluated the role of the Brucella membrane fusogenic protein (Mfp) and outer membrane protein 19 (Omp19) in bacterial pathogenesis. In this study, we showed that B. abortus Δmfp::kan and Δomp19::kan deletion mutant strains have reduced persistence in vivo in C57BL/6 and interferon regulatory factor 1 (IRF-1) knockout (KO) mice. Additionally, 24 h after macrophage infection with a Δmfp::kan or Δomp19::kan strain expressing green fluorescent protein (GFP) approximately 80% or 65% of Brucella-containing vacuoles (BCVs) retained the late endosomal/lysosomal marker LAMP-1, respectively, whereas around 60% of BCVs containing wild-type S2308 were found in LAMP-1-negative compartments. B. abortus Δomp19::kan was attenuated in vivo but had a residual virulence in C57BL/6 and IRF-1 KO mice, whereas the Δmfp::kan strain had a lower virulence in these same mouse models. Furthermore, Δmfp::kan and Δomp19::kan strains were used as live vaccines. Challenge experiments revealed that in C57BL/6 and IRF-1 KO mice, the Δmfp::kan strain induced greater protection than the vaccine RB51 and protection similar that of vaccine S19. However, a Δomp19::kan strain induced protection similar to that of RB51. Thus, these results demonstrate that Brucella Mfp and Omp19 are critical for full bacterial virulence and that the Δmfp::kan mutant may serve as a potential vaccine candidate in future studies.
authors: Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Job Alves
authors: JA
authors: de Souza Filho
authors: Departamento de Bioquímica, Universidade de Brasília, Brasília, DF, Brazil.
authors: Vicente
authors: V
authors: de Paulo Martins
authors: Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Priscila Carneiro
authors: PC
authors: Campos
authors: Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Juliana
authors: J
authors: Alves-Silva
authors: Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Nathalia V
authors: NV
authors: Santos
authors: Departamento de Bioquímica, Universidade Federal de Juiz de Fora Gerais, Governador Valadares, MG, Brazil.
authors: Fernanda Souza
authors: FS
authors: de Oliveira
authors: Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Gustavo B
authors: GB
authors: Menezes
authors: Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors: Vasco
authors: V
authors: Azevedo
authors: Instituto de Biotecnología, CICVyA-INTA, Buenos Aires, Argentina.
authors: Silvio Lorenzo
authors: SL
authors: Cravero
authors: Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil scozeus@icb.ufmg.br.
authors: Sergio Costa
authors: SC
authors: Oliveira
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics* / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000276:immunology; D002004:Brucella Vaccine / Q000276:immunology; D002003:Brucella abortus / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity*; D002006:Brucellosis / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D017353:Gene Deletion; D049452:Green Fluorescent Proteins / Q000096:biosynthesis; D050856:Interferon Regulatory Factor-1 / Q000235:genetics; D008074:Lipoproteins / Q000235:genetics* / Q000276:immunology; D051907:Lysosomal Membrane Proteins / Q000378:metabolism; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D050576:Membrane Fusion Proteins / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D014611:Vaccination; D037521:Virulence Factors / Q000235:genetics* / Q000276:immunology; D052118:Lysosomal-Associated Membrane Protein 1
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002004:Brucella Vaccine; D049452:Green Fluorescent Proteins; D050856:Interferon Regulatory Factor-1; D008074:Lipoproteins; D051907:Lysosomal Membrane Proteins; D050576:Membrane Fusion Proteins; D037521:Virulence Factors; C052255:Lamp1 protein, mouse; D052118:Lysosomal-Associated Membrane Protein 1; C097319:OMP19 protein, Brucella abortus
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