大肠杆菌感染后家蝇幼虫的细胞免疫反应

摘要

目的探讨家蝇3龄幼虫被大肠杆菌感染后的细胞免疫反应.方法 (1)观察家蝇3龄幼虫感染大肠杆菌后不同时间血淋巴细胞总数(THC)、各类血细胞比例及形态的变化.(2)用比色法分别测定感染后不同时间家蝇3龄幼虫血清中酸性磷酸酶(ACP)及过氧化氢酶(CAT)活性的变化.(3)用聚丙烯酰胺凝胶电泳法测定感染后不同时间家蝇3龄幼虫血清中二酚氧化酶(DPO)活性的变化.结果 (1)感染后4 h、8 h、16 h、24 h THC均有显著增加(P<0.01),(2)感染后4 h、8 h、16 h组的浆血胞和粒血胞的比例明显增加(P<0.01),而珠血胞在感染后各时间组的比例均明显减少(P<0.01),各时间组原血胞和类绛血胞的比例均无明显变化(P>0.05).(3)浆血胞出现细胞变形、空泡等形态变化.(4)大肠杆菌感染后各时间组血清中ACP及CAT活性显著高于对照组(P<0.01),活性分别在感染后8 h、16 h达高峰后逐渐下降.(5)家蝇幼虫血清中二酚氧化酶(DPO)活性在感染后4 h上升,16 h达高峰后下降.结论家蝇幼虫感染大肠杆菌后诱发体内细胞免疫反应,不仅出现血淋巴细胞形态和数量的变化,而且还有血细胞合成、释放多种参与微生物杀灭、清除的酶.%Objective To explore the cell immunity of the 3rd stage larva of Musca domestica after being infected by Escherichia coli. Methods (1) To observe changes in the number of total hemocytes (THC) and the proportion morphous of hemocytes of the 3rd stage larva of Musca domestica after being infected by E. coli. (2) The active changes of acid phosphatase (ACP) and catalase (CAT) in the sera of the 3rd stage larva of Musca domestica at different times after being infected by E. coli were assayed by the colorimetric method. (3) The active changes of diphenol oxidase (DPO) in the sera of the 3rd stage larva of Musca domestica at different times after being infected were assayed by PAGE. Results (1) Compared with the control groups, the number of total hemocytes (THC) of infection in the 4 h, 8 h, 16 h, and 24 h groups increased significantly (P<0.01). (2) The proportion of plasmatocytes and granulocytes of the 4 h, 8 h and 16 h groups after infection were significantly increased (P<0.01) and the proportion of sphrulocytes of all time groups after infection were significantly decreased (P<0.01). However, the proportion of prohemocytes and oenocytoids of the all time groups were not obviously different (P>0.05). (3) Vacuolation and morpholysis were found in plasmatocytes after being infected by E. coli. (4) The activities of both phosphatase (ACP) and catalase (CAT) in the sera of the all time groups were much higher than that of the control groups at 4 h, 8 h, 16 h and 24 h (P<0.01), and the peaks of the two enzymes activity appeared at 8 h and 16 h after infection, respectively, then gradually decreased. (5)Diphenol oxidase (DPO) existed in the Musca domestica larva, and its optical density value increased at 4 h after infection, and the peak of optical density value appeared at 16 h, then gradually decreased. Conclusion Cell immunity of the Musca domestica larva was induced by infection with E. coli, which included a change in the morphology and quantity of hemocytes, and hemocytes could synthesize and release various kinds of enzymes to kill microorganisms.