Application of the bacterial outer membrane vesicles in vaccine design

Outer membrane vesicles (OMVs) are extracellular structures produced by most gram-negative bacteria, including pathogens of humans and animals. OMVs play an important role in the physiology of microorganisms and are an integral part of many biological processes. Following the discovery that they are able to transport many biomolecules, also these which have the ability to interact with the immune system, their potential use as non-replicating vaccines has become an important aspect of immunotherapeutic researches. These nano-sized elements exhibit remarkable potential for immunomodulation of immune response, thanks to the ability to deliver naturally or artificially incorporated antigens within their structure. First vaccine based on outer membrane vesicles was developed almost 30 years ago against Neisseria meningitidis serogroup B. This review presents some basic information on biogenesis and functions of OMVs. It also provides examples of pathogens, whose OMVs (in natural or modified form) have been used in the development of immunogenic vaccines against the organisms from which the vesicles had been obtained. OMVs are proving to be more versatile than first conceived and may become important part of biotechnology research, not limited to medical applications.