摘要
Immunoglobulin (Ig) M production can be induced by the interaction of thymus-independent type-2 (TI-2) antigen (Ag) with B cell Ag receptors (BCRs) without the involvement of conventional T cells;for IgG production through the same process, however, a second signal is required. Previous studies have reported that invariant natural killer T (iNKT) cells may be responsible for the second signal involved in IgG production. In the present study, we addressed whether human iNKT cells could participate in the production of Ig against TI-2 Ag in vitro. Two major distinct subsets of human iNKT cells, CD4<sup>+</sup> CD8β<sup>-</sup> (CD4) and CD4<sup>-</sup> CD8β<sup>-</sup> [double negative (DN)] cells, were generated from peripheral blood monocytes from a healthy volunteer. BCR engagement, triggered by anti-IgM antibody stimulation, examined here as a model of BCR engagement triggered by TI-2 Ag, induced abundant IgM production by B cells. Both CD4 and DN iNKT cells reduced IgM production and conversely enhanced IgG production in a dose-dependent manner. In addition, IgG production by CD19<sup>+</sup>CD27<sup>-</sup> (naïve) and CD19<sup>+</sup>CD27<sup>+</sup> (memory) B cells was predominantly promoted by DNiNKT cells rather than CD4 iNKT cells;nevertheless, IgM production by both B cell subsets was similarly reduced by either subset of iNKT cells. These results suggest that the DN iNKT subsets may preferentially promote Ig class switching by B cells upon stimulation with TI-2 Ag.
Immunoglobulin (Ig) M production can be induced by the interaction of thymus-independent type-2 (TI-2) antigen (Ag) with B cell Ag receptors (BCRs) without the involvement of conventional T cells;for IgG production through the same process, however, a second signal is required. Previous studies have reported that invariant natural killer T (iNKT) cells may be responsible for the second signal involved in IgG production. In the present study, we addressed whether human iNKT cells could participate in the production of Ig against TI-2 Ag in vitro. Two major distinct subsets of human iNKT cells, CD4<sup>+</sup> CD8β<sup>-</sup> (CD4) and CD4<sup>-</sup> CD8β<sup>-</sup> [double negative (DN)] cells, were generated from peripheral blood monocytes from a healthy volunteer. BCR engagement, triggered by anti-IgM antibody stimulation, examined here as a model of BCR engagement triggered by TI-2 Ag, induced abundant IgM production by B cells. Both CD4 and DN iNKT cells reduced IgM production and conversely enhanced IgG production in a dose-dependent manner. In addition, IgG production by CD19<sup>+</sup>CD27<sup>-</sup> (naïve) and CD19<sup>+</sup>CD27<sup>+</sup> (memory) B cells was predominantly promoted by DNiNKT cells rather than CD4 iNKT cells;nevertheless, IgM production by both B cell subsets was similarly reduced by either subset of iNKT cells. These results suggest that the DN iNKT subsets may preferentially promote Ig class switching by B cells upon stimulation with TI-2 Ag.
作者
Tomomitsu Miyasaka
Yurie Watanabe
Yukiko Akahori
Namiko Miyamura
Keiko Ishii
Yuki Kinjo
Yoshitsugu Miyazaki
Tian-Yi Liu
Yasushi Uemura
Kazuyoshi Kawakami
Tomomitsu Miyasaka;Yurie Watanabe;Yukiko Akahori;Namiko Miyamura;Keiko Ishii;Yuki Kinjo;Yoshitsugu Miyazaki;Tian-Yi Liu;Yasushi Uemura;Kazuyoshi Kawakami(Department of Medical Microbiology, Mycology and Immunology, Tohoku University Graduate School of Medicine, Sendai, Japan;Department of Chemotherapy and Mycoses, National Institute of Infectious Diseases, Tokyo, Japan;Division of Immunology, Aichi Cancer Center Research Institute (ACCRI), Nagoya, Japan;Key Laboratory of Cancer Center, Chinese PLA General Hospital, Beijing, China;Division of Cancer Immunotherapy, Exploratory Oncology Research & Clinical Trial Center, National Cancer Center (NCC), Kashiwa, Japan)
