Essential Role of LFA-1 in Activating Th2-Like Responses by α-Galactosylceramide-Activated NKT Cells

Abstract

NKT cells produce large amounts of cytokines associated with both the Th1 (IFN-γ) and Th2 (IL-4) responses following stimulation of their invariant Vα14 Ag receptor. The role of adhesion molecules in the activation of NKT cells by the Vα14 ligand α-galactosylceramide (α-GalCer) remains unclear. To address this issue, LFA-1−/− (CD11a−/−) mice were used to investigate IL-4 and IFN-γ production by NKT cells following α-GalCer stimulation. Intriguingly, LFA-1−/− mice showed increased IL-4, IL-5, and IL-13 production and polarized Th2-type responses in response to α-GalCer in vitro and in vivo. Furthermore, the Th2-specific transcription factor GATA-3 was up-regulated in α-GalCer-activated NKT cells from LFA-1−/− mice. These results provide the first genetic evidence that the adhesion receptor LFA-1 has a crucial role in Th2-polarizing functions of NKT cells.