Invariant natural killer T (/NKT) cells are a unique lymphocyte subpopulation with potent immunomodulatory properties. They can produce copious amounts of pro- and/or anti-inflammatory cytokines, yet the mechanisms governing the type of immune responses they elicit are not fully understood. Conventional T cell activation can be achieved or augmented by glycosylphosphatidylinositol (GPI)-anchored proteins. Whether this is also true for /NKT cells is essentially unexplored. I hypothesized that ligation of GPI-anchored proteins such as Thy-1 and CD55 will enhance / NKT cell activation leading to robust cytokine production. Using flow cytometry, mouse /NKT cells were found to constitutively express Thy-1. Thy-1 engagement combined with classical TCR stimulation led to /NKT cell activation and cytokine production as measured by ELISA and RT-qPCR. Similarly, human /NKT cells expressed CD55, the cross-linking of which enhanced TCR-mediated activation. Overall, I have demonstrated that GPI-anchored proteins play a significant role in the magnitude of /NKT cell responses
