Construction of a novel bivalent DNA vaccine against SARS-CoV-2 and influenza A virus H3N2 and evaluation of its immunogenicity in mice
10.3760/cma.j.cn112309-20220417-00119
- VernacularTitle:新型冠状病毒和甲型流感病毒双价DNA疫苗的构建与免疫原性研究
- Author:
Chengcheng ZHAI
1
;
Di HAN
;
Yao DENG
;
Jiao REN
;
Wen WANG
;
Donghong WANG
;
Wenling WANG
;
Long GAO
;
Wenjie TAN
Author Information
1. 内蒙古科技大学包头医学院公共卫生学院，包头 014000
- Keywords:
SARS-CoV-2;
Influenza A virus;
DNA vaccine;
Humoral immunity;
Cellular immunity
- From:
Chinese Journal of Microbiology and Immunology
2022;42(9):683-690
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To construct a bivalent DNA vaccine against SARS-CoV-2 and influenza A virus H3N2 and to evaluate its immunogenicity in mice.Methods:The coding sequences for spike 1 (S1) protein of SARS-CoV-2 Beta variant and hemagglutinin (HA) of influenza A virus Cambodia (H3N2) strain were codon-optimized and synthesized. The two coding genes were ligated by the self-cleaving 2A peptide using over-lapping PCR to construct S1-2A-HA fragment, which was inserted into pVRC vector to construct the bivalent DNA vaccine, named as pVRC-S1-2A-HA. Indirect immunofluorescence assay (IFA) and Western blot were performed to detect the expression of S1 and HA proteins. BALB/c mice were immunized with pVRC-S1-2A-HA by intramuscular injection and electroporation. The humoral immune responses induced in mice were detected by indirect ELISA, pseudovirus neutralization assay and hemagglutination inhibition assay. Cellular immune responses were detected by IFN-γ ELISPOT, intracellular cytokine staining (ICS) and cytometric bead array (CBA).Results:The bivalent DNA vaccine pVRC-S1-2A-HA could express S1 and HA proteins in vitro. Specific cellular immune responses against S1 protein and specific IgG antibody against HA protein were significantly induced in mice with single-dose immunization. The antigen-specific immunity was significantly enhanced after booster immunization. The geometric mean titer (GMT) of specific IgG antibody increased to 3 251 for S1 protein and 45 407 for HA protein after two-dose immunization. Moreover, the S1-specific T cells increased to 1 238 SFC/10 6 cells. ICS results indicated that the booster vaccination induced CD4 + T and CD8 + T cells to produce IL-2, IFN-γ and TNF-α in mice. The secretion of various cytokines including IL-2, IL- 4, IL-6, IL-10 and IFN-γ in mouse splenocytes was induced after single-dose immunization. Conclusions:A bivalent DNA vaccine against SARS-CoV-2 and influenza A virus H3N2 was constructed and could induce S1- and HA-specific humoral and cellular immune responses in mice, suggesting the great potential of it for further development and application.
