Functional subsets of intestinal NKT cells (MUC3P.942)

NKT cells constitute a distinct population of lymphocytes characterized by their reactivity to glycolipids presented by CD1d. Although they are found at a relatively low frequency, because of their clonal specificity and rapid cytokine production, they have been reported to influence many types of immune responses. Recently NKT cells have been divided into functional subsets analogous to T helper (Th) Th1, Th2 and Th17 cell subsets, called NKT1, NKT2 and NKT17. We have examined if similar functional subsets are found in the mouse intestine. NKT cells are found at a low frequency in intraepithelial lymphocytes (IEL) of the small and large intestine and a higher prevalence in lamina propria lymphocytes (LPL). We analyzed intestinal NKT cells using flow cytometry to explore the transcription factors and surface markers expressed by these cells. We found out that all the functional subsets are represented in intestinal NKT cells, however, the percentages of each subset in the intestine are different from those found in spleen. We also evaluated the response of intestinal iNKT cells to the agonist α-Galactosylceramide. We observed that, in response to in vivo exposure to the potent antigen α-Galactosylceramide, intestinal NKT cells produced IFN-γ, TNF-α and GM-CSF and increased expression of activation markers, as CD69 and CD40L, suggesting that cells with an NKT1 function are most prevalent. We are now exploring how the microbiota affects the functions of intestinal NKT cells.