Thymic stromal lymphopoietin production in DN32.D3 invariant natural killer T (iNKT) cell line and primary mouse liver iNKT cells

BACKGROUND: Invariant natural killer T (iNKT) cells are known as the fast responder in allergic inflammation and the source of interleukin (IL)-4, IL-13, and interferon-gamma. Absence of iNKT cells down-regulated thymic stromal lymphopoietin (TSLP) production at the early stage of type 2 immune responses in the airway. However, it has not been reported whether iNKT cells are able to produce TSLP via stimulation of T-cell receptor (TCR). OBJECTIVE: We aimed to evaluate TSLP production from iNKT cells by TCR specific stimulations with anti-CD3/CD28 antibodies and α-galactoceramide (α-GalCer). METHODS: DN32.D3 iNKT cell line was stimulated with anti-CD3/CD28 antibodies, and TSLP production was measured in culture supernatants. Next, to confirm the TSLP production in primary mouse iNKT cells, the cells were sorted using α-GalCer-CD1d tetramer from mouse liver, and stimulated with anti-CD3/CD28 antibodies and α-GalCer. Then, cytokine productions were evaluated by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. RESULTS: TCR specific stimulation in DN32.D3 cells induced TSLP production as well as signature cytokines of iNKT cells. On the other hand, isolated primary mouse iNKT cells from liver did not show any induction of TSLP by TCR specific stimulations including anti-CD3/CD28 antibodies and α-GalCer, on the contrary to other cytokines. CONCLUSION: This study suggested the possibility of TSLP production in iNKT cells, especially from DN32.D3 although primary mouse liver iNKT cells showed a different result.