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.
Subject(s)
Antigens, Bacterial/genetics , Bacterial Outer Membrane Proteins/genetics , Brucella abortus/immunology , Brucella abortus/pathogenicity , Brucellosis/immunology , Lipoproteins/genetics , Membrane Fusion Proteins/genetics , Virulence Factors/genetics , Animals , Antigens, Bacterial/immunology , Bacterial Outer Membrane Proteins/immunology , Brucella Vaccine/immunology , Brucella abortus/genetics , Brucellosis/pathology , Brucellosis/prevention & control , Gene Deletion , Green Fluorescent Proteins/biosynthesis , Interferon Regulatory Factor-1/genetics , Lipoproteins/immunology , Lysosomal Membrane Proteins/metabolism , Macrophages/immunology , Macrophages/microbiology , Membrane Fusion Proteins/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Vaccination , Virulence Factors/immunologyABSTRACT
A meningite asséptica (MA) é uma entidade anatomoclínica aguda, benigna, de ocorrência rara na população geral, com manifestações clínicas variáveis e ausência de patógenos identificáveis no líquido cefalorraquidiano. Sua prevalência é maior associada a administração ou presença de algum medicamento e/ou doença autoimune, respectivamente. Seu diagnóstico é dificultado devido à inespecificidade das manifestações clínicas e laboratoriais, o que resulta em hospitalizações, propedêutica invasiva e antibioticoterapia desnecessárias.
Aseptic meningitis (AM) is an acute and benign condition, rare in the general population, characterized by nonspecific clinical manifestations associated with changes on cerebrospinal fluid (CSF) sample analysis, including negative cultures. The subject of analysis is the relationship between medication intake and autoimmune diseases with the occurrence of AM. It has been concluded that this condition occurs more often in case both causes are associated. The diagnosis of AM is difficult because of the nonspecifity of the signs and symptoms and findings on CSF analysis, which results in unnecessary hospitalizations, invasive exams and antibiotic therapy.
