誤って選択されたCD8T細胞がCD8遺伝子メチル化によって無活性化され,細胞が死亡する
G A Pestano1, Y Zhou, L A Trimble
1Department of Cancer Immunology and AIDS, Dana Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston MA 02115, USA.
まとめ
誤った選択されたCD8細胞は,ポスチム性品質管理メカニズムによって浄化されます. T細胞受容体 (TCRs) とCD8コアレセプター (CD8 coreceptors) の活性化に失敗すると,アポトーシス (apoptosis) が引き起こされ,自己免疫疾患が予防されます.
科学分野:
- 免疫学 免疫学とは
- 分子生物学は分子生物学である.
- 細胞生物学 細胞生物学
背景:
- T細胞は,適切な機能を確保するために,胸膜の選択を受けます.
- MHCクラスIのT細胞受容体 (TCR) 認識が欠如したCD8細胞の誤った選択は,胸膜スクリーニングを逃れることができます.
- このような潜在的に自己反応性T細胞を排除するために,ポストタイミックメカニズムが不可欠である.
研究 の 目的:
- 誤った選択されたCD8細胞を浄化するポストタイミック品質管理メカニズムを定義する.
- 非機能的なTCRを持つCD8細胞の除去につながる分子イベントを解明する.
- 自身免疫疾患に対するこの品質管理経路の欠陥の影響を理解する.
主な方法:
- CD8細胞集団の分析.
- T細胞受容体 (TCR) とCD8核受容体の関与の調査.
- リメチル化によるCD8遺伝子阻害を含む遺伝子発現の変化の評価.
- 表面FasとFasリガンドの上昇調節の評価.
- 細胞アポトーシスの誘導と分析.
主要な成果:
- 誤って選択されたCD8細胞は,TCRとCD8核受容体をMHC分子と同時に結合させることができない.
- この失敗は,リメチル化によるCD8遺伝子発現抑制を含むプロセスを開始します.
- このプロセスは,表面FasとFasリガンドの上昇調節に終結し,アポトーシスにつながります.
- MHCとの継続的なTCR-CD8の共同関与は,生存チェックポイントとして機能します.
結論:
- 新しく開発されたポスチム性品質管理経路は,非機能的なTCRを持つCD8細胞を排除する.
- この経路は,TCRとCD8コレセプターのMHCとの連携した関与に依存しています.
- この死亡シグナル伝達経路の分子欠陥は,二重陰性T細胞の拡大と全身的自己免疫疾患に寄与する.
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