Coronavirus vaccine based on controllable secretory expression of attenuated salmonella, preparation method therefor, and application thereof

A SARS-CoV-2 coronavirus vaccine based on secretory expression of attenuated Salmonella, comprising:

• an antigen expression vector and an antigen presentation system for the SARS-CoV-2 coronavirus vaccine,
• wherein the attenuated Salmonella is htrA gene-deficient attenuated Salmonella VNP20009 (Ah-1);
• wherein the antigen expression vector is an oral vaccine presentation system capable of secretory expression through a Salmonella type III secretory expression system induced by an intracellular environment of antigen-presenting cells, the Salmonella type III antigen secretory expression system comprises a type III secretion system promoter and a signal peptide sequence and a plasmid anti-loss element;
• wherein the type III secretion system promoter comprises a sifB promotor having a gene sequence of the nucleotide sequence shown in SEQ ID No. 4, the signal peptide sequence comprises a SseJ signal peptide having a gene sequence of the nucleotide sequence shown in SEQ ID No. 5;
• and the plasmid anti-loss element is an AT element having a gene sequence of the nucleotide sequence shown in SEQ ID No. 10;
• and
• wherein the SARS-CoV-2 vaccine comprises a recombinant VNP20009 (Ah-1) strain that expresses a SARS-CoV-2 spike protein (S protein) RBD structural domain located at positions 319-541 of full amino acid sequence of the S protein, and the RBD structural domain has a gene sequence of the nucleotide sequence shown in SEQ ID No. 6.