The Role of Invariant Natural Killer T Cells in Cancer

Invariant natural killer T (iNKT) cells are a unique subset of T lymphocytes that recognize
glycolipid antigens presented by the class I-like non-polymorphic histocompatibility
complex (MHC) molecule, CD1d. They express both innate and adaptive immune cells’
surface receptors, but act more like cells of the innate immune system. Although iNKT
cells represent a relatively small population of T lymphocytes, they can rapidly produce
copious amounts of cytokines after activation which can polarize different axes of the
immune response. Many glycolipid agonists have been discovered of which the marine
sponge-derivative called α-Galactosylceramide (α-GalCer) is a potent ligand for iNKT
cells. iNKT cells have been described by many researchers as a critical
immunotherapeutic target characterized by having tumor-suppressive potential. However,
their actual role in immune responses is still unclear. In addition, the need for appropriate
preclinical models that mimic human diseases is important for better understanding the
iNKT cell biology. This review describes the characteristics of iNKT cells and their role in
immunotherapy in cancers such as multiple myeloma and how they can interact with the
components of the neighbouring environment.