Vaccination with a bacterial peptide conjugated to SARS-CoV-2 receptor-binding domain accelerates immunity and protects against COVID-19

Athanasios Blanas, Haiko Karsjens, Aafke de Ligt, Elisabeth J. M. Huijbers, Karlijn van Loon, Stepan S. Denisov, Canan Durukan, Diederik J. M. Engbersen, Jan Groen, Sven Hennig, Tilman M. Hackeng, Judy R. van Beijnum, Arjan W. Griffioen

Research output: Contribution to journalArticleAcademicpeer-review


Poor immunogenicity of critical epitopes can hamper vaccine efficacy. To boost immune recognition of non- or low-immunogenic antigens, we developed a vaccine platform based on the conjugation of a target protein to a chimeric designer peptide (CDP) of bacterial origin. Here, we exploited this immune Boost (iBoost) technology to enhance the immune response against the receptor-binding domain (RBD) of the SARS-CoV-2 spike glycoprotein. Despite its fundamental role during viral infection, RBD is only moderately immunogenic. Immunization studies in mice showed that the conjugation of CDP to RBD induced superior immune responses compared to RBD alone. CDP-RBD elicited cross-reactive antibodies against the variants of concern Delta and Omicron. Furthermore, hamsters vaccinated with CDP-RBD developed potent neutralizing antibody responses and were fully protected from lung lesion formation upon challenge with SARS-CoV-2. In sum, we show that the iBoost conjugate vaccine technology provides a valuable tool for both quantitatively and qualitatively enhancing anti-viral immunity.
Original languageEnglish
Article number104719
Pages (from-to)1-19
Number of pages20
Issue number8
Early online date5 Jul 2022
Publication statusPublished - 19 Aug 2022


  • Biological sciences
  • Immune response
  • Immunology
  • Virology

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