Identification of liver-specific CD24+ invariant NK T cells with low granzyme B production and high proliferative capacity

Invariant NK T (iNKT) cells are innate-like lymphocytes that can recognize the lipid Ag presented by MHC I like molecule CD1d. Distinct tissue distribution of iNKT cells subsets implies a contribution of these subsets to their related tissue regional immunity. iNKT cells are enriched in liver, an organ with unique immunological properties. Whether liver-specific iNKT cells exist and dedicate to the liver immunity remains elusive. Here, a liver-specific CD24(+) iNKT subset is shown. Hepatic CD24(+) iNKT cells show higher levels of proliferation, glucose metabolism, and mTOR activity comparing to CD24(-) iNKT cells. Although CD24(+) iNKT cells and CD24(-) iNKT cells in the liver produce similar amounts of cytokines, the hepatic CD24(+) iNKT cells exhibit lower granzyme B production. These liver-specific CD24(+) iNKT cells are derived from thymus and differentiate into CD24(+) iNKT in the liver microenvironment. Moreover, liver microenvironment induces the formation of CD24(+) conventional T cells as well, and these cells exhibit higher proliferation ability but lower granzyme B production in comparison with CD24(-) T cells. The results propose that liver microenvironment might induce the generation of liver-specific iNKT subset that might play an important role in maintaining liver homeostasis.

Automated summary

Invariant NK T (iNKT) cells are enriched in the liver, where a liver-specific CD24(+) iNKT subset with high proliferation and metabolism activity is found but lower granzyme B production. The liver microenvironment also influences the differentiation of conventional T cells, leading to the generation of CD24(+) T cells with different functional characteristics. These findings suggest that the liver microenvironment may induce the generation of a liver-specific iNKT subset that plays a crucial role in maintaining liver homeostasis.