Diversification of the VH3-53 immunoglobulin gene segment by somatic hypermutation results in neutralization of SARS-CoV-2 virus variants.

Abstract

COVID-19 induces re-circulating long-lived memory B cells (MBC) that, upon re-encounter with the pathogen, are induced to mount immunoglobulin responses. During convalescence, antibodies are subjected to affinity maturation, which enhances the antibody binding strength and generates new specificities that neutralize virus variants. Here, we performed a single-cell RNA sequencing analysis of spike-specific B cells from a SARS-CoV-2 convalescent subject. After COVID-19 vaccination, matured infection-induced MBC underwent recall and differentiated into plasmablasts. Furthermore, the transcriptomic profiles of newly activated B cells transiently shifted toward the ones of atypical and CXCR3+ B cells and several B-cell clonotypes massively expanded. We expressed monoclonal antibodies (mAbs) from all B-cell clones from the largest clonotype that used the VH3-53 gene segment. The in vitro analysis revealed that some somatic hypermutations enhanced the neutralization breadth of mAbs in a putatively stochastic manner. Thus, somatic hypermutation of B-cell clonotypes generates an anticipatory memory that can neutralize new virus variants.

• Authors: Matthias Bruhn, Maureen Obara, Abdus Salam, Bibiana Costa, Annett Ziegler, Inken Waltl, Andreas Pavlou, Markus Hoffmann, Theresa Graalmann, Stefan Pöhlmann, Axel Schambach, Ulrich Kalinke
• Journal: European journal of immunology (Eur J Immunol) Pg. e2451056 (Apr 09 2024) ISSN: 1521-4141 [Electronic] Germany
• PMID: 38593351 (Publication Type: Journal Article)
• Copyright: © 2024 The Authors. European Journal of Immunology published by Wiley‐VCH GmbH.