Immunogenicity of novel DNA vaccines encoding receptor-binding domain (RBD) dimer-Fc fusing antigens derived from different SARS-CoV-2 variants of concern.
J Med Virol
; 95(2): e28563, 2023 02.
Article
in English
| MEDLINE | ID: covidwho-2237521
ABSTRACT
The continuously emerging of severe acute respiratory syndrome coronavirus-2 variants of concern (VOCs) led to a decline in effectiveness of the first-generation vaccines. Therefore, optimized vaccines and vaccination strategies, which show advantages in protecting against VOCs, are urgently needed. Here we constructed an optimized DNA vaccine plasmid containing built-in CpG adjuvant, and designed vaccine candidates encoding five forms of antigens derived from Wuhan-Hu-1. The results showed that plasmid with receptor binding domain (RBD) dimer-Fc fusing antigen (2RBD-Fc) induced the highest level of RBD-specific IgG and neutralizing antibodies in mice. Then 2dRBD-Fc and 2omRBD-Fc vaccines, respectively derived from delta and omicron VOCs, were constructed. The 2dRBD-Fc induced potent humoral and cellular immune responses, while the immunogenicity of 2omRBD-Fc was low. We also observed that sequential immunization with 2RBD-Fc, 2dRBD-Fc and 2omRBD-Fc effectively elicited neutralizing antibodies against each immunized strain, and RBD-specific T cell responses. To be noted, the Wuhan-Hu-1, delta and omicron neutralizing antibody titers induced by sequential immunization were comparable to that induced by repetitive immunization with 2RBD-Fc, 2dRBD-Fc or 2omRBD-Fc respectively. The results suggest that sequential immunization with DNA vaccines encoding potent antigens derived from different VOCs, may be a promising strategy to elicit immune responses against multiple variants.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Vaccines, DNA
/
COVID-19 Vaccines
/
COVID-19
Topics:
Vaccines
/
Variants
Limits:
Animals
/
Humans
Language:
English
Journal:
J Med Virol
Year:
2023
Document Type:
Article
Affiliation country:
Jmv.28563
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