The clinical implication and molecular mechanism of preferential IL-4 production by modified glycolipid-stimulated NKT cells
Shinji Oki, Asako Chiba, Takashi Yamamura, Sachiko Miyake
Shinji Oki, Asako Chiba, Takashi Yamamura, Sachiko Miyake
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Article Immunology

The clinical implication and molecular mechanism of preferential IL-4 production by modified glycolipid-stimulated NKT cells

Abstract

OCH, a sphingosine-truncated analog of α-galactosylceramide (αGC), is a potential therapeutic reagent for a variety of Th1-mediated autoimmune diseases through its selective induction of Th2 cytokines from natural killer T (NKT) cells. We demonstrate here that the NKT cell production of IFN-γ is more susceptible to the sphingosine length of glycolipid ligand than that of IL-4 and that the length of the sphingosine chain determines the duration of NKT cell stimulation by CD1d-associated glycolipids. Furthermore, IFN-γ production by NKT cells requires longer T cell receptor stimulation than is required for IL-4 production by NKT cells stimulated either with immobilized mAb to CD3 or with immobilized “αGC-loaded” CD1d molecules. Interestingly, transcription of IFN-γ but not that of IL-4 was sensitive to cycloheximide treatment, indicating the intrinsic involvement of de novo protein synthesis for IFN-γ production by NKT cells. Finally, we determined c-Rel was preferentially transcribed in αGC-stimulated but not in OCH-stimulated NKT cells and was essential for IFN-γ production by activated NKT cells. Given the dominant immune regulation by the remarkable cytokine production of ligand-stimulated NKT cells in vivo, in comparison with that of (antigen-specific) T cells or NK cells, the current study confirms OCH as a likely therapeutic reagent for use against Th1-mediated autoimmune diseases and provides a novel clue for the design of drugs targeting NKT cells.

Authors

Shinji Oki, Asako Chiba, Takashi Yamamura, Sachiko Miyake

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Induction of NF-κB family members in activated NKT cells. (A) Plotted va...
Induction of NF-κB family members in activated NKT cells. (A) Plotted values represent data of Affymetrix microarray analysis for the indicated genes.The αGC-stimulated (red lines) or OCH-stimulated (green lines) cells as well as unstimulated liver NKT cells were analyzed at the same time points and the data are presented as the relative value for stimulated NKT cells when the value in NKT cells derived from untreated animals was defined as 1. (B) Real-time PCR analysis for the same genes as in A. Data are presented as described in Figure 4. (C) Sorted liver NKT cells were pretreated with CsA or CHX and were stimulated with immobilized mAb to CD3, and comparative values of c-Rel transcripts relative to GAPDH were determined. (D) Sorted liver NKT cells were stimulated with immobilized mAb to CD3 for the indicated periods of time and then were cultured without stimulation for up to a total of 120 minutes after the initial stimulation. Total RNA was extracted from each sample and analyzed for relative amounts of transcripts of IFN-γ or IL-4 (left), or c-Rel (right). The amount of RNA derived from unstimulated NKT cells was defined as 100%.