日本血吸虫紫外线致弱尾蚴免疫小鼠攻击感染后的组织细胞反应

Tissue Reactions in UV-attenuated Cercariae Immunized C57BL / 6 Mice After Challenged with Cercariae of Schistosoma japonicum

目的观察日本血吸虫紫外线致弱尾蚴疫苗(UVC)免疫动物攻击感染后的局部组织免疫病理变化。方法将70只C57BL/6小鼠随机分为疫苗免疫组和感染对照组。疫苗组小鼠接种紫外线致弱日本血吸虫尾蚴后5周,再经腹部皮肤攻击感染正常日本血吸虫尾蚴(800±50)条;感染对照组经皮肤感染同量尾蚴。于攻击感染后6～120h的不同时间点各剖杀小鼠5只,取攻击部位皮肤及/或肺组织,进行病理学观察。结果UVC疫苗免疫小鼠攻击感染日本血吸虫尾蚴后,皮肤炎症反应较感染对照出现早、反应强烈、持续时间长,EOS百分比高,但肺部出血斑点出现时间(72h)迟于感染对照组(48h)。72～120h,疫苗组小鼠肺部局灶性炎症明显,肉芽肿样结节形成,肺泡壁多正常,而感染对照组小鼠肺组织炎症轻,但肺泡壁水肿明显,且有较多红细胞渗出。结论紫外线致弱尾蚴疫苗免疫增强了小鼠皮肤及肺组织的细胞反应及其杀虫作用。

Objective To observe tissue reactions of skin and lung of UV-attenuated cercariae immunized C57BL/6 mice after challenged with cercariae of Schistosoma japonicum. Method Seventy mice of C57BL/6 were divided into two groups, UV-attenuated cercariae immunized （UVC） group and infection control group randomly. The mice of the UVC group were challenged with（800±50）cercariae of Schistosomajaponicum five weeks after immunization. The mice of the infection control group were challenged with the same number of cercariae. Local skin and lung samples from the mice of each group were taken at certain time points from 6 to 120 hours after the infection for pathological observation. Result The skin inflammation in mice of UVC group post challenge infection appeared early, and the cellular reactions against schistosomula in the skin tissues were acute and persistent, in which the percent of eosinophils was high. However, in the infection control group, the skin inflammation emerged lately, and the cellular reactions against schistosomula were weaker than those in UVC group. The bleeding speckles on the lung＇s surface of mice in UVC group appeared lately at 72 h after the challenge. In contrast, the bleed spots appeared early by 48 h after the infection in the infection control group. From 72 h to 120 h after challenge infection, pulmonary inflammation was obvious, granulomas formed, but the most walls of pulmonary alveolus were normal in the mice of UVC group. However, in control group, the pulmonary inflammation was weak but there were a lot of red blood cells seeping into the pulmonary alveolus walls. Conclusion UVC vaccine increases cellular immune response of the host and enhances the role of killing schistosomula.