SARS-CoV Spike Proteins Expressed by the Vaccinia Virus Tiantan Strain: Secreted SQ Protein Induces Robust Neutralization Antibody in Mice

Abstract

The spike (S) glycoprotein of severe acute respiratory syndrome coronavirus (SARS-CoV) is a major target in the development of diagnostic assays and vaccines, but its antigenic and immunogenic properties remain unclear. Seven SARS-CoV spike proteins (S, SQ, S1, RBD, S2, S2Q, and CX) were generated using the modified vaccinia virus (Tiantan strain) as a vector, and their antigenicity and immunogenicity were evaluated. The secreted SQ protein in which the transmembrane domain was deleted, as well as the full-length spike protein, showed the most potential to induce the production of neutralizing antibody (nAb) in mice. S1 and RBD proteins initialized significantly lower levels of nAb production. In addition, the S proteins were recognized specifically by the sera of convalescent patients with SARS, and that of mice immunized with inactivated SARS-CoV, but did not react with anti-sera of HCoV-OC43 or HCoV-229E, or sera from healthy donors (although RBD showed a false-positive in 1 of 55 control samples of human sera). Our results demonstrate that SQ protein may be an effective vaccine candidate and a convenient and safe diagnostic antigen for SARS-CoV.

Protective Efficacy of the Conserved NP, PB1, and M1 Proteins as Immunogens in DNA- and Vaccinia Virus-Based Universal Influenza A Virus Vaccines in Mice

“…Vaccinia virus Tiantan is a characteristic strain with a wide host range, powerful multiplication capacity, abundant regions containing unnecessary genes, a high capacity for foreign gene insertion, noncarcinogenicity, lasting immunity, and cytoplasmic replication, and a long history of applications in humans. It has been used widely as a recombinant vaccine vector for many years, and multiple recombinant vaccinia viruses based on the Tiantan strain have been reported (51)(52)(53)(54)(55). Previous studies suggested that the vaccinia virus Tiantan strain-based vector system is suitable for expressing foreign genes and constructing recombinant vaccines, and the resulting recombinant vaccines are safe and effective in animals.…”

The Amino Acids 736–761 of the MERS-CoV Spike Protein Induce Neutralizing Antibodies: Implications for the Development of Vaccines and Antiviral Agents

“…Testing for immunogen reactivity was performed using the rRBD or various peptides as the antigen in an ELISA. The ELISA procedure was carried out as previously described (10,24).…”

“…M iddle East respiratory syndrome coronavvirus (MERS-CoV), a novel b coronavirus, was recently identified as the causative agent of a severe acute respiratory illness in humans in the Middle East (24). This finding has raised serious concerns about the possibility of a pandemic infection similar to that caused by severe acute respiratory syndromecoronavirus (SARS-CoV) (2,20).…”

The Novel Replication-defective Vaccinia Virus (Tiantan Strain)–based Hepatitis C Virus Vaccine Induces Robust Immunity in Macaques

“…21,33,34 The gene was conventionally subcloned into the poxvirus shuttle vector pJSA1175 derived in our laboratory, which places the insert gene under the control of the vaccinia virus p7.5 promoter and provides flanks for recombination at the TK locus of NTV (Figure 1a). 21,[35][36][37][38] NTVJTK + ΔCK, replication-defective Tiantan strain vaccinia virus(NTV) with the CK region deleted (Supplementary Figure S1), was used as the original virus. 15,39 Recombinant viruses were isolated following transfection of this plasmid into infected primary chick embryo fibroblasts (day 9 of gestation) by transient dominant selection using LacZ.…”