Role of bacterial outer membrane vesicles in immune evasion during infection

Bacterial infections remain a major global public health challenge and are further exacerbated by the increasing prevalence of antimicrobial resistance. Furthermore, bacterial pathogens employ diverse strategies to escape host immune surveillance and establish persistent infections. In recent years, bacterial outer membrane vesicles (OMVs) have attracted considerable attention because of their important roles in host-pathogen interactions. Emerging evidence suggests that OMVs participate in bacterial immune evasion through multiple mechanisms. However, the complex mechanisms underlying OMVs-mediated modulation of host immunity remain incompletely understood. Here, we comprehensively review the current understanding of OMVs and the mechanisms contributing to bacterial immune evasion. Particular emphasis is placed on their roles in silencing host immune genes, regulating survival signaling pathways, promoting bacterial intracellular colonization, facilitating biofilm formation, modulating host inflammation and immune tolerance, neutralizing host immune effectors, and inducing epigenetic reprogramming. In addition, we discuss current and emerging strategies targeting OMV-mediated immune evasion. This review summarizes recent findings and provides insights into potential directions for future anti-infective research and therapeutic development.