Wang Zhaofei, Guo Mengting, Kong Licheng, Gao Ya, Ma Jingjiao, Cheng Yuqiang, Wang Henan, Yan Yaxian, Sun Jianhe
Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Shanghai Jiao Tong University, Shanghai 200240, China.
Vaccines (Basel). 2021 Feb 22;9(2):184. doi: 10.3390/vaccines9020184.
() serotype 2 (SS2) is the causative agent of swine streptococcosis and can cause severe diseases in both pigs and humans. Although the traditional inactive vaccine can protect pigs from SS2 infection, novel vaccine candidates are needed to overcome its shortcomings. Three infection-associated proteins in -muramidase-released protein (MRP), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and DLD, a novel putative dihydrolipoamide dehydrogenase-have been previously identified by immunoproteomic assays. In this study, the effective immune protection of the recombinant trivalent protein GAPDH-MRP-DLD (JointS) against SS2, SS7, and SS9 was determined in zebrafish. To improve the immune efficacy of JointS, monophosphoryl lipid A (MPLA) as a TLR4 agonist adjuvant, which induces a strong innate immune response in the immune cells of mice and pigs, was combined with JointS to immunize the mice. The results showed that immunized mice could induce the production of a high titer of anti- antibodies; as a result, 100% of mice survived after SS2 infection. Furthermore, JointS provides good protection against virulent SS2 strain infections in piglets. Given the above, there is potential to develop JointS as a novel subunit vaccine for piglets to prevent infection by SS2 and other serotypes.
2型猪链球菌（SS2）是猪链球菌病的病原体，可在猪和人类中引起严重疾病。尽管传统的灭活疫苗可以保护猪免受SS2感染，但仍需要新型候选疫苗来克服其缺点。先前通过免疫蛋白质组学分析鉴定出三种与感染相关的蛋白质——溶菌酶释放蛋白（MRP）、甘油醛-3-磷酸脱氢酶（GAPDH）和一种新型假定的二氢硫辛酰胺脱氢酶DLD。在本研究中，在斑马鱼中测定了重组三价蛋白GAPDH-MRP-DLD（JointS）对SS2、SS7和SS9的有效免疫保护作用。为了提高JointS的免疫效果，将单磷酰脂质A（MPLA）作为TLR4激动剂佐剂与JointS联合免疫小鼠，MPLA可在小鼠和猪的免疫细胞中诱导强烈的先天免疫反应。结果表明，免疫小鼠可诱导产生高滴度的抗体；因此，100%的小鼠在感染SS2后存活。此外，JointS对仔猪的强毒SS2菌株感染提供了良好的保护。综上所述，开发JointS作为一种新型亚单位疫苗用于仔猪预防SS2和其他血清型感染具有潜力。
