単一のT細胞受容体が自己および外部のMHCの両方を認識する方法
Leremy A Colf1, Alexander J Bankovich, Nicole A Hanick
1Howard Hughes Medical Institute, Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
Cell
|April 10, 2007
まとめ
T細胞受容体 (TCRs) は,外来タンパク質と自己タンパク質を認識することができ,この過程をアロ活性性と呼びます. この研究では,2C TCRは,異なるメジャー・ヒストコンパティビリティ・コンプレックス (MHC) リガンドを結合するために異なる構造的戦略を使用しており,TCRのクロス反応性における分子模倣の考え方に異議を唱えていることが明らかになりました.
科学分野:
- 免疫学 免疫学とは
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
背景:
- アルファベータT細胞受容体 (TCRs) は,自己および外因メジャーヒストコンパティビリティ複合体 (MHC) タンパク質との交叉反応を示し,これはオロ活性性として知られる現象である.
- 多様なリガンドのTCR認識の構造的基礎を理解することは,免疫学と移植にとって極めて重要です.
研究 の 目的:
- 2C TCRの異なったMHCペプチド複合体との交叉反応の基礎となる構造的メカニズムを解明する.
- 2C TCRが異種リガンド (H-2L(d) -QL9) と自己リガンド (H-2K(b) -dEV8) をどのように誘導するかを比較する.
主な方法:
- X線結晶学を使用して,H-2L(d) -QL9.9で複合した2C TCRの2.35A構造を決定しました.
- 外国 (H-2L(d) -QL9) と自己 (H-2K(b) -dEV8) リガンドの両方に結合した2C TCRの比較構造分析.
主要な成果:
- 2C TCRは,外来H-2L (d) -QL9と自己H-2K (b) -dEV8リガンドを結合するために異なる構造戦略を採用しています.
- TCRは,各リガンドのMHCポリモルフィック残留物とペプチド抗原の両方とユニークな対対接触を行います.
- 2C TCRとL(d) - QL9複合体の間で,より大きな構造的な互補性が観察されました.
- エンジニアリングされた高親和性TCR変種は,変化したTCR-CDR3α-ペプチド相互作用にもかかわらず,野生型の結合方向性を維持しました.
結論:
- 単一のTCRは,異なる結合メカニズムを通じて異なるリガンドを認識することができ,分子模倣なしに交叉反応性を示す.
- これらの発見は,T細胞受容体アロ活性とリガンド差別の構造的基礎に関する新しい洞察を提供します.
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