猪链球菌多表位融合疫苗MVPLM-SS的构建及免疫效果评价OA

[Objective]Based on the immunodominant epitopes of PdhA,Ldh,and MalX,a multi-epitope candidate vaccine against Streptococcus suis(SS)was designed with the aim of developing a novel vaccine with broad-spectrum protection.[Method]Using immunoinformatics methods,the BCL epitopes,CTL epitopes,and HTL epitopes were predicted from the immunogenic proteins PdhA,Ldh,and MalX of Streptococcus suis.High-scoring surface-exposed immunodominant epitopes were then linked via AAY,KK,and GPGPG linkers to construct the multi-epitope vaccine MVPLM-SS(multi-epitope vaccine PdhA-Ldh-MalX-SS).Finally,its safety and immunogenicity were evaluated through clinical monitoring,antibody titer detection,cytokine assays,and survival curve analysis.[Result]A total of 14 dominant epitope peptides were screened and used to construct the multi-epitope fusion protein MVPLM-SS.The resulting protein exhibited favorable hydrophilicity,thermal stability,and structural stability.Molecular docking analysis further predicted effective binding between MVPLM-SS and Toll-like receptor 4(TLR4).Subsequently,the recombinant expression plasmid pET28a(+)-sumo-MVPLM-SS was successfully constructed,and the target protein of approximately 63 kD was expressed.Compared with the PBS/adjuvant control group,MVPLM-SS immunization significantly raised serum IgG level,IL-4,and IFN-γ mass concentrations,prolonged survival,and mitigated histopathological damage in the brain and lung of mice.[Conclusion]The designed multi-epitope fusion vaccine MVPLM-SS exhibited a rational structure and was efficiently expressed in Escherichia coli.In mice,it induced robust humoral immune responses and significantly attenuated histopathological lesions caused by Strepto-coccus suis infection.These findings support MVPLM-SS as a promising candidate for the development of broad-spectrum vaccines against this pathogen.