Division of Animal Infectious Diseases in the State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
FEMS Microbiol Lett. 2011 Mar;316(2):115-22. doi: 10.1111/j.1574-6968.2010.02200.x. Epub 2011 Jan 19.
Streptococcus suis serotype 2 (SS2) is an emerging zoonotic pathogen. Prevention and control of the diseases caused by SS2 bacteria are hampered by the lack of effective vaccines. We report that an in vivo-induced protein HP0245 was located at the cell surface of SS2. The extracellular peptide of HP0245 was produced in Escherichia coli BL21 (DE3). Its immunogenicity was compared with SS2 bacterin. Like SS2 bacterin, protein HP0245(EC) formulated in aluminum hydroxide adjuvant provided 100% protection in mice challenged with a low dose (2 × LD(50) ) of SS2. However, 80% and 50% survival rates were observed in mice vaccinated with HP0245(EC) and SS2 bacterin, respectively, challenged with a high dose (5 × LD(50) ) of SS2. Immunization with HP0245(EC) induced significantly higher IgG2a titers compared with SS2 bacterin, which was more effective for opsonophagocytosis. No obvious histopathological change was found in the HP0245(EC) -vaccinated mice after challenge with the low dose of SS2, whereas a mild lesion was observed in the meninges of the mice vaccinated with SS2 bacterin. Homologous hp0245 genes with the highly conserved coding sequence of the extracellular peptide exist in all sequenced SS2 strains as well as most S. suis reference strains. Thus, HP0245 could be considered as a promising vaccine candidate for SS2.
猪链球菌 2 型（SS2）是一种新兴的人畜共患病病原体。由于缺乏有效的疫苗，SS2 细菌引起的疾病的预防和控制受到阻碍。我们报告说，一种体内诱导的蛋白 HP0245 位于 SS2 的细胞表面。HP0245 的细胞外肽在大肠杆菌 BL21（DE3）中产生。其免疫原性与 SS2 菌苗进行了比较。与 SS2 菌苗一样，用氢氧化铝佐剂配制的蛋白 HP0245（EC）在 2×LD50 低剂量 SS2 攻击的小鼠中提供了 100%的保护。然而，用 HP0245（EC）和 SS2 菌苗接种的小鼠的存活率分别为 80%和 50%，用 5×LD50 高剂量 SS2 攻击。与 SS2 菌苗相比，用 HP0245（EC）免疫诱导的 IgG2a 滴度显著升高，对调理吞噬作用更有效。用 HP0245（EC）免疫的小鼠在低剂量 SS2 攻击后未发现明显的组织病理学变化，而用 SS2 菌苗接种的小鼠脑膜中有轻度病变。所有测序的 SS2 菌株以及大多数 S. suis 参考菌株中都存在与细胞外肽高度保守的编码序列同源的 hp0245 基因。因此，HP0245 可以被认为是 SS2 的一种有前途的候选疫苗。
