Abstract
Administration of NKT cell ligands, α-galactosylceramide (α-GalCer) resulted in the activation of both cytokine production and natural killing. These responses were abolished in both CD1d-deficient mice and Vα14NKT-deficient mice. Therefore, NKT cells have been considered to be responsible cells for both cytokine production and natural killing. Here, we reevaluated a critical role of NKT and NK cells at early time after α-GalCer administration. Intracellular staining experiments demonstrated that NKT cells were the earliest source of both IL-4 and IFN-γ production after α-GalCer administration in vivo. However, these α-GalCer- activated NKT cells exhibited no significant natural killing activity. In contrast, isolated NK1.1+CD3- classical NK cells exhibited greatly enhanced natural killing activity 6 h after α-GalCer administration. NKT cells, however, exhibited a strong cytotoxicity when they were activated and expanded with α-GalCer plus IL-2 in vitro. These results indicated that NKT cells act as regulatory cells via production of cytokines for activation of NK cell-mediated cytotoxicity in vivo at early phase after α-GalCer administration. Thus, NK cells rather than NKT cells may be a crucial early activated killer induced by α-GalCer in vivo.
Original language | English (US) |
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Pages (from-to) | 5-11 |
Number of pages | 7 |
Journal | Immunology Letters |
Volume | 95 |
Issue number | 1 |
DOIs | |
State | Published - Aug 15 2004 |
Keywords
- Cytotoxicity
- NK
- NKT
- α-GalCer
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology