猪链球菌2型荚膜缺失株生物学特性及其免疫保护性

Characterization of a nonencapsulated mutant of Streptococcus suis serotype 2 and evaluation of its protective abilities in a mouse model

对前期构建的猪链球菌2型中国强致病株05ZYH33荚膜缺失株Δcps2B进行相关生物学特性及免疫保护性研究。通过比较野生株05Z33和荚膜缺失株Δcps2B生物学特性发现,Δcps2B株显微形态发生改变,失去与2型荚膜特异抗血清发生凝集反应的能力,突变株更易被全血清除,对上皮细胞HEP-2的粘附能力增强。动物保护性实验结果表明该荚膜缺失株Δcps2B具有良好的免疫保护作用。研究结果提示荚膜在细菌抵抗吞噬和细菌粘附过程中发挥重要作用。

The biological function of a formerly constructed nonencapsuled mutant Δcps2B from 05ZYH33 was characterized,and its protection against infection was evaluated.We found that Δcps2B have reduced ability to form long chain capsule polysaccharide and no longer agglutinated with the specific anti-capsular serum.The Δcps2B could be cleared more easily by the whole blood of human and piglet,while the capacity of adhesion to epithelial cells increased greatly.Animal infection experiment demonstrated that the Δcps2B protect mice from lethal challenge with S.suis 2.These observations indicate that the capsule plays an essential role in the pathogenesis and invasiveness of S.suis 2.