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Publication Abstract from PubMed

Vaccination with different vaccines has been implemented globally to counter the continuous COVID-19 pandemic. However, the vaccine-elicited antibodies have reduced efficiency against the highly mutated Omicron sub-variants. Previously, we developed a protein subunit COVID-19 vaccine called ZF2001, based on the dimeric receptor-binding domain (RBD). This vaccine has been administered using different dosing intervals in real-world setting. Some individuals received three doses of ZF2001, with a one-month interval between each dose, due to urgent clinical requirements. Others had an extended dosing interval of up to five months between the second and third dose, a standard vaccination regimen for the protein subunit vaccine against hepatitis B. In this study, we profile B cell responses in individuals who received three doses of ZF2001, and compared those with long or short dosing intervals. We observed that the long-interval group exhibited higher and broader serologic antibody responses. These responses were associated with the increased size and evolution of vaccine-elicited B-cell receptor repertoires, characterized by the elevation of expanded clonotypes and somatic hypermutations. Both groups of individuals generated substantial amounts of broadly neutralizing antibodies (bnAbs) against various SARS-CoV-2 variants, including Omicron sub-variants such as XBB. These bnAbs target four antigenic sites within the RBD. To determine the vulnerable site of SARS-CoV-2, we employed cryo-electron microscopy to identify the epitopes of highly potent bnAbs that targeted two major sites. Our findings provide immunological insights into the B cell responses elicited by RBD-based vaccine, and suggest that a vaccination regimen of prolonging time interval should be used in practice.

Dosing interval regimen shapes potency and breadth of antibody repertoire after vaccination of SARS-CoV-2 RBD protein subunit vaccine.,Guo S, Zheng Y, Gao Z, Duan M, Liu S, Du P, Xu X, Xu K, Zhao X, Chai Y, Wang P, Zhao Q, Gao GF, Dai L Cell Discov. 2023 Jul 28;9(1):79. doi: 10.1038/s41421-023-00585-5. PMID:37507370^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.