Proteomic analysis of Exosomes from Brucella abortus infected Macrophages Reveals Mechanisms of Immune Evasion and Host Modulation

ABSTRACT: Brucella abortus is an intracellular pathogen capable of establishing chronic infections through sophisticated immune evasion mechanisms. Among these, exosomes derived from infected macrophages have emerged as key vehicles of pathogen–host communication. In this study, we performed a comparative proteomic analysis of exosomes secreted by RAW 264.7 macrophages infected with B. abortus at 8 and 24 hours post-infection using LC-MS/MS. Exosomes displayed dynamic and functionally distinct proteomic profiles depending on infection time. At 8 hpi, profiles showed enrichment of proteins related to biosynthesis, energy metabolism, and endoplasmic reticulum processing, along with reduced abundance of proteins associated with lysosomes and antigen presentation. At 24 hpi, profiles shifted toward mitochondrial and redox regulatory pathways, while suppression of immune-related processes persisted. Exclusive proteins were identified in each phase, including retromer complex components and immune mediators such as Csf3, Gsdmd, and Ifi35. Notably, bacterial proteins were consistently detected in exosomes: GroEL and SodC were present at both 8 and 24 hpi, whereas Omp19, Omp2b, DnaK, and the invasion protein B homolog BAB1_0368 were restricted to the early phase. These findings indicate that exosomes derived from B. abortus–infected macrophages are not mere byproducts, but active mediators of bacterial persistence and immune modulation, with potential as biomarkers and therapeutic tools.

INSTRUMENT(S):

ORGANISM(S): Brucella Abortus Str. 2308 A

SUBMITTER: Guillermo Nourdin  

LAB HEAD: Angel A. Oñate

PROVIDER: PXD066999 | Pride | 2026-05-14

REPOSITORIES: Pride