致病性小肠结肠炎耶尔森菌外膜蛋白A对SD大鼠免疫保护作用研究

目的 研究致病性小肠结肠炎耶尔森菌外膜蛋白A(OmpA)对大鼠的免疫保护作用,为研制疫苗提供技术基础。方法 将SD大鼠随机分为3组,通过腹股沟注射方式对大鼠进行免疫,包括OmpA免疫组(OmpA+弗氏不完全佐剂)、对照组(PBS+弗氏不完全佐剂)和空白对照组(未做任何处理)。经首次免疫(0.58 mg/只)和加强免疫(1 mg/只)后,用两个浓度的致病性小肠结肠炎耶尔森菌Ye92010(10⁶ CFU、10⁸ CFU)对OmpA免疫组和对照组进行攻毒,观察攻毒后各组大鼠的体征、排菌情况以及组织病理学改变。结果 攻毒后OmpA免疫组与对照组大鼠均出现厌食、被毛杂乱、粪便呈松软非颗粒状等症状。OmpA免疫组大鼠粪便排菌时间均为14 d,对照组大鼠粪便排菌时间分别为17 d(低剂量攻毒)和21 d(高剂量攻毒)。OmpA免疫组的肝、脾、肠组织病变程度相对较轻,组织变性及坏死灶情况明显优于对照组。结论 结合各组大鼠粪便排菌时间和大体观察结果,表明实验大鼠经OmpA免疫后可有效抵御致病性小肠结肠炎耶尔森菌的肠道定植,且组织病理学改变明显减轻,提示OmpA对SD大鼠具有良好的免疫保护作用。

Immunoprotection of outer membrane protein A from pathogenic Yersinia enterocolitica on rat

The aim of the study is to evaluate the protective effect of pathogenic Yersinia enterocolitica OmpA on rat immunoprotection, providing technical basis for vaccines development. Inguinal injection was performed on SD rats which were randomly divided into OmpA protection group (OmpA with freund’s incomplete adjuvant), control group (PBS with freund’s incomplete adjuvant), and non-treatment control group. After first immunization (0.58 mg/per rat) and enhance immunization (1 mg/per rat), high pathogenicity Yersinia Ye92010 (10⁶ CFU, 10⁸ CFU) were infected. Then the body assymptomatic, fecal bacteria discharge and histopathological changes of liver, spleen and terminal ileum of experimental rats were observed. After infection, the pathological symptoms were appeared like anorexia, hair disorder, loose stools,etc. The bacteria fecal excretion time in the OmpA immunization group was 14 d, and in the control group was 17 d (low dose attack group) and 21 d (high dose attack group). The histopathological changes and necrotic foci of the OmpA immune group were better than those in the control group, and the pathological changes of the liver, spleen and intestine were also relatively mild. According to the bacteria fecal excretion time and general observation, experimental rats immunized by OmpA could effectively resist pathogenic Y. enterocolitica colonization, the organ pathological changes is also significantly reduced. It indicates that OmpA has a good immune protection effect on SD rats.