alpha-galactosylceramide induces early B-cell activation through IL-4 production by NKT cells.

alpha-Galactosylceramide (alpha-GalCer), a glycolipid antigen, specifically activates natural killer T (NKT) cells by a CD1d-restricted mechanism. In this work, we found that in vivo administration of alpha-GalCer resulted in the activation of B cells in addition to NKT cells, namely, alpha-GalCer administration caused upregulation of the early activation marker, CD69, on both NKT and B cells. In addition, expression of B7.2 and I-A(b) on B cells was greatly upregulated by alpha-GalCer. However, serum levels of IgE, IgG1, and IgG2a were not significantly changed within 48 h. In the present experiments, it was also demonstrated that the upregulation of CD69 expression by alpha-GalCer was strongly blocked by anti-IL-4 monoclonal antibody. Moreover, B-cell activation by alpha-GalCer was not observed in NKT-deficient mice. These results suggested that antigen-stimulated NKT cells might play a critical role not only in early defense mechanisms but also in early B-cell activation through IL-4 production.

Kitamura H ，Ohta A ，Sekimoto M ，Sato M ，Iwakabe K ，Nakui M ，Yahata T ，Meng H ，Koda T ，Nishimura S ，Kawano T ，Taniguchi M ，Nishimura T ... -  《CELLULAR IMMUNOLOGY》

Enhanced gamma interferon production through activation of Valpha14(+) natural killer T cells by alpha-galactosylceramide in interleukin-18-deficient mice with systemic cryptococcosis.

Kawakami K ，Kinjo Y ，Yara S ，Uezu K ，Koguchi Y ，Tohyama M ，Azuma M ，Takeda K ，Akira S ，Saito A ... -  《-》

A novel function of Valpha14+CD4+NKT cells: stimulation of IL-12 production by antigen-presenting cells in the innate immune system.

Tomura M ，Yu WG ，Ahn HJ ，Yamashita M ，Yang YF ，Ono S ，Hamaoka T ，Kawano T ，Taniguchi M ，Koezuka Y ，Fujiwara H ... -  《JOURNAL OF IMMUNOLOGY》

NKT cells act as regulatory cells rather than killer cells during activation of NK cell-mediated cytotoxicity by alpha-galactosylceramide in vivo.

Chamoto K ，Takeshima T ，Kosaka A ，Tsuji T ，Matsuzaki J ，Togashi Y ，Ikeda H ，Nishimura T ... -  《IMMUNOLOGY LETTERS》

Phenotypical and functional alterations during the expansion phase of invariant Valpha14 natural killer T (Valpha14i NKT) cells in mice primed with alpha-galactosylceramide.

Ikarashi Y ，Iizuka A ，Koshidaka Y ，Heike Y ，Takaue Y ，Yoshida M ，Kronenberg M ，Wakasugi H ... -  《-》