SARS-CoV-2に対する抗体免疫の進化

Christian Gaebler¹, Zijun Wang¹, Julio C C Lorenzi¹

¹Laboratory of Molecular Immunology, The Rockefeller University, New York, NY, USA.

Nature

|January 18, 2021

まとめ

SARS-CoV-2感染後に抗体のレベルは低下するが,記憶B細胞は持続し,進化する. これらの記憶B細胞は,抗体の効能と変異に対する耐性を改善し,継続的な免疫適応を示唆しています.

科学分野:

免疫学
ウイルス学
感染症

背景:

重症急性呼吸器症候群コロナウイルス2型 (SARS-CoV-2型) は,世界的な死亡率と罹病率を大幅に引き起こす.
SARS-CoV-2 感染後の抗体反応は変化し,中和抗体は保護を提供する.
感染後の記憶B細胞の反応の長期的質と性質は,ほとんど特徴づけられていない.

研究の目的:

SARS-CoV-2に対する体内記憶反応のダイナミクスを調査する.
抗体位数,中和活性,および記憶B細胞群の変化を時間とともに評価する.
SARS-CoV-2感染後の記憶B細胞の特徴と進化を調べる.

主な方法:

抗体 (IgM,IgG,IgA) 位数とプラズマ中和活性について,感染後1. 3ヶ月と6. 2ヶ月で87人の個体で長期分析を行った.
受容体結合領域 (RBD) 固有の記憶B細胞の定量化と特徴づけ
メモリB細胞の体性高変異,RBD変異に対する抗体の耐性,および効力の分析.
腸バイオプシーにおけるSARS-CoV-2核酸と免疫反応の検出.

主要な成果:

抗体位数 (IgM,IgG) と中和活性が感染後6. 2カ月で著しく低下し,IgAは影響が少ない.
研究期間中,RBD特異的な記憶B細胞の数は安定していました.
メモリーB細胞はクローナルターンオーバーを示し,体性高変異の増加,RBD変異に対する強化された耐性,およびより高い効能を持つ抗体を産生しました.
SARS-CoV-2の持続性は,個々のサブセットの小腸で検出されました.

結論:

SARS-CoV-2に対する体内免疫反応には,持続的で進化する記憶B細胞集団が含まれています.
記憶B細胞の成熟と抗体の進化は,持続的な抗原に対する反応を示唆する.
発見は,急性抗体減少を超えて広がるSARS-CoV-2感染に対するダイナミックな適応免疫反応を示しています.

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