Transcriptome analysis of Brucella abortus S19∆per immunized mouse spleen revealed activation of MHC-I and MHC-II pathways.

The mouse (Mus musculus) has been extensively used for studying brucellosis, regarding pathogenesis, immunity and the evaluation of vaccines and therapeutics. In this work, RNA-seq was applied to explore the immunological potential of a live Brucella abortus S19∆per, a perosamine synthetase gene mutant of B. abortus S19. Comparison of transcriptome data was carried out for identifying differentially expressed genes among PBS (control) and B. abortus S19∆per immunized mice at 15 days post-immunization. Functional analysis revealed 545 significant differentially expressed genes related to mouse immunity. Specific activation of MHC-I and MHC-II antigen-processing pathways were identified as the highly enriched pathways based on Kyoto Encyclopedia of Genes and Genomes annotation. Other major immune response pathways regulated within the host were NF-kappa B signalling, chemokine signalling, T-cell receptor pathway, apoptosis, TNF signalling and nucleotide-binding oligomerization domain-like receptor signalling. These data provided new insights into the molecular mechanisms of B. abortus S19∆per-induced immune response in mice spleen that might facilitate the development of a highly immunogenic vaccine against brucellosis.