Bacterial outer membrane vesicles: Potential and applications in next-generation vaccines

Outer membrane vesicles, released by Gram-negative bacteria, have attracted increasing attention in biotechnology due to their structural similarity to bacterial cells, their composition rich in immunogenic factors, and their role in pathogen-host interactions. Although they are involved in multiple functions related to bacterial pathophysiology, their applicability as vaccine platforms has emerged as a promising strategy for the development of next-generation vaccines. OMVs offer significant advantages over traditional vaccines, including the induction of robust T cell-mediated immune responses, the natural presence of pathogen-associated molecular patterns with adjuvant effects, and the possibility of bioengineering to display heterologous antigens. Preclinical trials using OMVs have demonstrated effective protection against infection, highlighting their versatility and safety. In addition, their stability, lack of replicative capacity, and ease of production make OMVs a highly attractive platform, including for emerging diseases and applications in cancer immunotherapy. This chapter discusses the structural and functional aspects of OMVs, with emphasis on their innovative potential in the vaccine field, while also addressing the technological challenges related to their standardization, purification, and industrial scale-up.