ランプレイの3番目のリンパ球系統の進化的影響
Masayuki Hirano1, Peng Guo, Nathanael McCurley
1Emory Vaccine Center and Department of Pathology and Laboratory Medicine, Emory University, 1462 Clifton Road North-East, Atlanta, Georgia 30322, USA.
Nature
|August 13, 2013
まとめ
のない脊椎動物は,免疫グロブリンベースの受容体ではなく,ユニークな変性リンパ球受容体 (VLR) を利用します. この研究は,VLRC受容体を発現する新しいT細胞のようなリンパ球系統を特定し,古代の免疫システムの複雑性を示唆しています.
科学分野:
- 免疫学 免疫学とは
- 進化生物学の進化生物学について
- 脊椎動物学 脊椎動物学
背景:
- の脊椎動物 (gnathostomes) は,免疫グロブリンスーパーファミリー受容体 (T細胞とB細胞受容体) に基づく適応免疫を持っています.
- のない脊椎動物 (サイクロストーム) は,ランプリやハグフィッシュのように,異なるリンパ球集団で,VLRAやVLRBを含む変性リンパ球受容体 (VLRs) のレピートタンパク質 (ルシンの豊富なタンパク質) を利用しています.
- 以前の研究でVLRAとVLRBが特定されましたが,他のVLR発現リンパ球の存在と機能は不明でした.
研究 の 目的:
- のない脊椎動物における新しいリンパ球系を特定し,特徴づけること.
- これらの新しいリンパ球の遺伝子と発達経路を調査する.
- 脊椎動物における適応性免疫システムの進化的起源を理解する.
主な方法:
- サイクロストームにおけるVLRC受容体を発現するリンパ球の識別と特徴付け.
- グナトストームとサイクロストームにおけるリンパ球の分化に関与する遺伝子オートロジの分析.
- "チモイド"の部領域におけるVLR集合とレパートリー多様化の調査.
主要な成果:
- VLRC受容体を発現するT細胞のようなリンパ球の新しい系統が定義されました.
- VLRC(+) とVLRA(+) リンパ球は,グナトストームT細胞の分化経路 (γδとαβT細胞) を共有する遺伝子オーソログを持っています.
- VLRCとVLRA受容体は,チモイド領域で組み立てられ,多様化し,細胞表面で発現します.
結論:
- 2つの原始的なT細胞系とプロトタイプのB細胞系のための遺伝プログラムは,おそらく最後の共通の脊椎動物の祖先 (約5億年前) に存在していた.
- 異なるT細胞のような系統の機能的専門化は,脊椎動物の免疫システムの古くからの特徴であるようです.
- この発見は,早期の適応性免疫の進化に関する私たちの理解を再構築します.
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