Activation and Function of iNKT and MAIT Cells

Cross-talk between iNKT cells and monocytes triggers an atheroprotective immune response in SLE patients with asymptomatic plaque

“…Beyond this little detailed information about iNKT cell phenotype in patients with atherosclerosis exists. We revealed that SLE-P patients had increased CD4 + iNKT cell number, IL-4 production and GATA-3 expression compared to SLE-NP patients; characteristic of NKT2 cells, a functional iNKT cell subset with anti-inflammatory properties (28). CD4 + iNKT cells have previously been isolated from human plaque tissue (26) and associated with Th2 responses in healthy donors (29) and cancer patients (30).…”

MAIT cells: not just another brick in the wall

“…This bias might suggest an evolutionary need for one or the other cell type 11. In many inflammatory diseases, systemic MAIT cell numbers are lowered compared with healthy controls, with a relative enrichment in the inflamed tissues 4 7. A similar situation was found in patients with AS and patients with RA, where MAIT cells were enriched in the synovial fluid and lowered systemically.…”

“…MAIT cell numbers are relatively high in humans (1–10% of circulating T cells, 20–45% of T cells in the liver and 3–5% of lymphoid cells in the intestinal mucosa), compared with numbers of iNKT cells. The opposite situation is present in mice, where iNKT cells are rather abundant compared with MAIT cells, the latter also not displaying a functionally mature phenotype as can be found in humans 7. This bias might suggest an evolutionary need for one or the other cell type 11.…”

“…They rapidly produce cytokines with a T H 1 (tumour necrosis factor (TNF) and interferon-gamma (IFNγ)) or T H 17 (IL-17A) profile upon T cell receptor (TCR)-dependent and TCR-independent signals 7. It is, thus, obvious that the activation of such potent cells incurs risks 8.…”

“…Here, they fully mature after thymic emigration, a process that depends on the presence of the commensal microbial flora and B cells 16. A hallmark of these cells is their highly restricted TCR Vα repertoire 7. They react to non-peptide antigens, bound by the non-classical class I antigen-presenting molecule, MR1 that is highly conserved across mammalian species (figure 1).…”