Immunogenicity of a vaccine candidate for severe fever with Thrombocytopenia syndrome virus that utilized an attenuated Salmonella delivery system expressing specific SFTSV antigens
Immunogenicity of a vaccine candidate for severe fever with Thrombocytopenia syndrome virus that utilized an attenuated Salmonella delivery system expressing specific SFTSV antigens
- 한국예방수의학회
- Journal of Preventive Veterinary Medicine
- Vol.48, No.2
- 2024.06
- 111 - 120 (10 pages)
Severe Fever with Thrombocytopenia Syndrome (SFTS) is a newly emerging tick-borne disease caused by the SFTS virus (SFTSV), which belongs to the phlebovirus in the Bunyaviridae family. SFTSV is enveloped with a tripartite ambisense RNA genome. The L segment encodes the viral RNA-dependent RNA polymerase, the M segment encodes the two glycoproteins, Gc and Gn, and the S segment encodes the nucleoprotein (NP) and the nonstructural protein (NSs). NP participates in ribonucleoprotein (RNP) packaging and commonly detected early after infection, suggesting that the N protein is possible to be used as a target antigen for early diagnosis of SFTSV infection. In this study, we analyzed a highly immunogenic multi-epitope using GnGc and NP genes from a consensus sequence of SFTSV strain isolated from infected patients in Korea. The selected genes are constructed to the expression vector plasmid pJHL65 and the recombinant plasmid vector was transformed into the Δasd Δlon ΔcpxR Salmonella Typhimurium attenuated strain JOL912 and the expression of these antigens was verified by immunoblotting assay. We observed the significant levels of systemic IgG and mucosal IgM responses against the JOL912-derived antigen in the immunized BALB/c mice. The level of CD3+CD4+, CD3+CD8+ T lymphocyte subpopulation and TNF-α were also highly regulated in splenic T cells re-stimulated in vitro with NP and Gn/Gc multi-epitope selected antigens. Therefore, immunized mice with NP and Gn/GC multi-epitope recombinant proteins of attenuated Salmonella delivery system elicited T cell-related immune response, inducing an effective immune response. In conclusion, the attenuated Salmonella expressing NP-GnGc multi-epitopes could be a novel vaccine candidate against the SFTS virus.