AUTHOR=Kinjo Yuki , Takatsuka Shogo , Kitano Naoki , Kawakubo Shun , Abe Masahiro , Ueno Keigo , Miyazaki Yoshitsugu 

TITLE=Functions of CD1d-Restricted Invariant Natural Killer T Cells in Antimicrobial Immunity and Potential Applications for Infection Control

JOURNAL=Frontiers in Immunology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.01266

DOI=10.3389/fimmu.2018.01266

ISSN=1664-3224

ABSTRACT=<p>CD1d-restricted invariant natural killer T (<italic>i</italic>NKT) cells are innate-type lymphocytes that express a T-cell receptor (TCR) containing an invariant α chain encoded by the <italic>Vα14</italic> gene in mice and <italic>Vα24</italic> gene in humans. These <italic>i</italic>NKT cells recognize endogenous, microbial, and synthetic glycolipid antigens presented by the major histocompatibility complex (MHC) class I-like molecule CD1d. Upon TCR stimulation by glycolipid antigens, <italic>i</italic>NKT cells rapidly produce large amounts of cytokines, including interferon-γ (IFNγ) and interleukin-4 (IL-4). Activated <italic>i</italic>NKT cells contribute to host protection against a broad spectrum of microbial pathogens, and glycolipid-mediated stimulation of <italic>i</italic>NKT cells ameliorates many microbial infections by augmenting innate and acquired immunity. In some cases, however, antigen-activated <italic>i</italic>NKT cells exacerbate microbial infections by promoting pathogenic inflammation. Therefore, it is important to identify appropriate microbial targets for the application of <italic>i</italic>NKT cell activation as a treatment or vaccine adjuvant. Many studies have found that <italic>i</italic>NKT cell activation induces potent adjuvant activities promoting protective vaccine effects. In this review, we summarize the functions of CD1d-restricted <italic>i</italic>NKT cells in immune responses against microbial pathogens and describe the potential applications of glycolipid-mediated <italic>i</italic>NKT cell activation for preventing and controlling microbial infections.</p>