XBB.1.16 に関する佐藤研[The Sato Lab @SystemsVirology]の研究成果とラモスさん[ramos2 @ramos262740691]の解説

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インドで生まれて世界中に拡散しはじめたオミクロンの新しい変異株 XBB.1.16 ――もう何世代目でしょうかね？――に関して、佐藤研がさっそく研究成果をプレプリントでリリースし、幸いにもラモスさんが早く気づいて注釈してくれてました。

さて、私の住む京都では、桜の花見シーズンと相まって、海外から大勢の観光客が押し寄せてきています。
そして、海外からの観光客だけでなく日本人でも、マスクを着けないで繁華街や観光スポットを歩き回る人たちが急増しました。
なんだかもうね・・・近いうちに京都発祥の XBB 系統の変異株が出てくるのではと非常に心配してます。

 

◆Virological characteristics of the SARS-CoV-2 Omicron XBB.1.16 variant【bioRxiv　2023年4月6日】

Abstract

At the end of March 2023, XBB.1.16, a SARS-CoV-2 omicron XBB subvariant, emerged and was detected in various countries. Compared to XBB.1.5, XBB.1.16 has two substitutions in the S protein: E180V is in the N-terminal domain, and T478K in the receptor-binding domain (RBD). We first show that XBB.1.16 had an effective reproductive number (Re) that was 1.27- and 1.17-fold higher than the parental XBB.1 and XBB.1.5, respectively, suggesting that XBB.1.16 will spread worldwide in the near future. In fact, the WHO classified XBB.1.16 as a variant under monitoring on March 30, 2023. Neutralization assays demonstrated the robust resistance of XBB.1.16 to breakthrough infection sera of BA.2 (18-fold versus B.1.1) and BA.5 (37-fold versus B.1.1). We then used six clinically-available monoclonal antibodies and showed that only sotrovimab exhibits antiviral activity against XBB subvariants, including XBB.1.16. Our results suggest that, similar to XBB.1 and XBB.1.5, XBB.1.16 is robustly resistant to a variety of anti-SARS-CoV-2 antibodies. Our multiscale investigations suggest that XBB.1.16 that XBB.1.16 has a greater growth advantage in the human population compared to XBB.1 and XBB.1.5, while the ability of XBB.1.16 to exhibit profound immune evasion is comparable to XBB.1 and XBB.1.5. The increased fitness of XBB.1.16 may be due to (1) different antigenicity than XBB.1.5; and/or (2) the mutations in the non-S viral protein(s) that may contribute to increased viral growth efficiency.