• Medientyp: E-Artikel
  • Titel: Homologous but not heterologous COVID-19 vaccine booster elicits IgG4+ B-cells and enhanced Omicron subvariant binding
  • Beteiligte: Hartley, Gemma E.; Fryer, Holly A.; Gill, Paul A.; Boo, Irene; Bornheimer, Scott J.; Hogarth, P. Mark; Drummer, Heidi E.; O’Hehir, Robyn E.; Edwards, Emily S. J.; van Zelm, Menno C.
  • Erschienen: Springer Science and Business Media LLC, 2024
  • Erschienen in: npj Vaccines, 9 (2024) 1
  • Sprache: Englisch
  • DOI: 10.1038/s41541-024-00919-8
  • ISSN: 2059-0105
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  • Beschreibung: AbstractBooster vaccinations are recommended to improve protection against severe disease from SARS-CoV-2 infection. With primary vaccinations involving various adenoviral vector and mRNA-based formulations, it remains unclear if these differentially affect the immune response to booster doses. We examined the effects of homologous (mRNA/mRNA) and heterologous (adenoviral vector/mRNA) vaccination on antibody and memory B cell (Bmem) responses against ancestral and Omicron subvariants. Healthy adults who received primary BNT162b2 (mRNA) or ChAdOx1 (vector) vaccination were sampled 1-month and 6-months after their 2nd and 3rd dose (homologous or heterologous) vaccination. Recombinant spike receptor-binding domain (RBD) proteins from ancestral, Omicron BA.2 and BA.5 variants were produced for ELISA-based serology, and tetramerized for immunophenotyping of RBD-specific Bmem. Dose 3 boosters significantly increased ancestral RBD-specific plasma IgG and Bmem in both cohorts. Up to 80% of ancestral RBD-specific Bmem expressed IgG1+. IgG4+ Bmem were detectable after primary mRNA vaccination, and expanded significantly to 5–20% after dose 3, whereas heterologous boosting did not elicit IgG4+ Bmem. Recognition of Omicron BA.2 and BA.5 by ancestral RBD-specific plasma IgG increased from 20% to 60% after the 3rd dose in both cohorts. Reactivity of ancestral RBD-specific Bmem to Omicron BA.2 and BA.5 increased following a homologous booster from 40% to 60%, but not after a heterologous booster. A 3rd mRNA dose generates similarly robust serological and Bmem responses in homologous and heterologous vaccination groups. The expansion of IgG4+ Bmem after mRNA priming might result from the unique vaccine formulation or dosing schedule affecting the Bmem response duration and antibody maturation.
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