Biotechnology Division, Korea Atomic Energy Research Institute, Jeongeup.
Brain Korea 21 Program for Leading Universities and Students, Department of Molecular Medicine, Chonnam National University Medical School, Gwangju.
J Infect Dis. 2017 Dec 27;217(1):93-102. doi: 10.1093/infdis/jix565.
Streptococcus agalactiae (group B streptococcus [GBS]) is a leading cause of invasive diseases in neonates and severe infections in elderly individuals. GBS serine-rich repeat glycoprotein 1 (Srr1) acts as a critical virulence factor by facilitating GBS invasion into the central nervous system through interaction with the fibrinogen Aα chain. This study revealed that srr1 is highly conserved, with 86.7% of GBS clinical isolates expressing the protein. Vaccination of mice with different Srr1 truncated peptides revealed that only Srr1 truncates containing the latch domain protected against GBS meningitis. Furthermore, the latch peptide alone was immunogenic and elicited protective antibodies, which efficiently enhanced antibody-mediated opsonophagocytic killing of GBS by HL60 cells and provided heterogeneous protection against 4 different GBS serogroups. Taken together, these findings indicated that the latch domain of Srr1 may constitute an effective peptide vaccine candidate for GBS.
无乳链球菌（B 群链球菌）是导致新生儿侵袭性疾病和老年人严重感染的主要原因。无乳链球菌富含丝氨酸的重复糖蛋白 1（Srr1）是一种关键的毒力因子，通过与纤维蛋白原 Aα 链相互作用促进无乳链球菌侵入中枢神经系统。本研究表明，srr1 高度保守，86.7%的无乳链球菌临床分离株表达该蛋白。用不同 Srr1 截断肽对小鼠进行疫苗接种的结果表明，只有含有闩锁结构域的 Srr1 截断肽能预防无乳链球菌脑膜炎。此外，单独的闩锁肽具有免疫原性，并能引发保护性抗体，这些抗体能有效地增强 HL60 细胞对无乳链球菌的抗体介导的调理吞噬作用，对 4 种不同的无乳链球菌血清群提供异质保护。综上所述，这些发现表明 Srr1 的闩锁结构域可能构成无乳链球菌有效的肽疫苗候选物。
