Regulatory roles of extracellular vesicles in immune responses against Mycobacterium tuberculosis infection

Abstract

Extracellular vesicles (EVs) are cystic vesicles naturally released by most mammalian cells and bacteria. EV contents include proteins, lipids, and nucleic acids. EVs can act as messengers to transmit a variety of molecules to recipient cells and thus play important regulatory roles in intercellular signal transduction. EVs, released by either a host cell or a pathogen, can carry pathogen-associated antigens and thus act as modulators of immune responses. EVs derived from Mycobacterium tuberculosis (Mtb)-infected cells can regulate the innate immune response through various pathways, such as regulating the release of inflammatory cytokines. In addition, EVs can mediate antigen presentation and regulate the adaptive immune response by transmitting immunoregulatory molecules to T helper cells. In this review, we summarize the regulatory roles of EVs in the immune response against Mtb.

Keywords: Extracellular vesicles; Exosomes; Mycobacterium tuberculosis; Infection; Antigen; Immune regulation

Core Tip: Extracellular vesicles (EVs) are nanoscale membrane-bound structures released by mammalian cells and bacteria and play essential regulatory roles in intercellular signal transduction and the immune response. In this review, we discuss the regulatory role of EVs released by Mycobacterium tuberculosis (Mtb)-infected cells in the anti-Mtb immune response. Specifically, we focus on providing the most cutting-edge information on EVs released by Mtb-infected cells regulating the body’s immune response, including the regulatory roles in innate and acquired immune responses. In addition, we describe the basis for EV-mediated regulation of the immune response in detail, i.e., the EVs released by Mtb-infected host cells contain Mtb-associated antigens.