Frontiers in Immunology (Oct 2024)

Analysis of B-cell receptor repertoire to evaluate the immunogenicity of SARS-CoV-2 RBD mRNA vaccine: MAFB-7256a (DS-5670d)

  • Goh Ohji,
  • Yohei Funakoshi,
  • Kimikazu Yakushijin,
  • Takaji Matsutani,
  • Tomoki Sasaki,
  • Takahiro Kusakabe,
  • Sakuya Matsumoto,
  • Taiji Koyama,
  • Yoshiaki Nagatani,
  • Keiji Kurata,
  • Shiro Kimbara,
  • Naomi Kiyota,
  • Naomi Kiyota,
  • Hironobu Minami,
  • Hironobu Minami

DOI
https://doi.org/10.3389/fimmu.2024.1468760
Journal volume & issue
Vol. 15

Abstract

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A monovalent Omicron XBB.1.5 mRNA RBD analogue vaccine, MAFB-7256a (DS-5670d), was newly developed and approved in Japan in the Spring of 2024 for the prevention of COVID-19. However, clinical efficacy data for this vaccine are currently lacking. We previously established the Quantification of Antigen-specific Antibody Sequence (QASAS) method to assess the response to SARS-CoV-2 vaccination at the mRNA level using B-cell receptor (BCR) repertoire assays and the Coronavirus Antibody Database (CoV-AbDab). Here, we used this method to evaluate the immunogenicity of MAFB-7256a. We analyzed repeated blood samples using the QASAS method from three healthy volunteers before and after MAFB-7256a vaccination. BCR response increased rapidly one week post-vaccination and then decreased, as with conventional vaccine. Notably, the matched sequences after MAFB-7256a vaccination specifically bound to the receptor-binding domain (RBD), with no sequences binding to other epitopes. These results validate that MAFB-7256a is an effective vaccine that exclusively induces antibodies specific for the RBD, demonstrating its targeted immunogenic effect.

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