中文摘要：

目的探讨湖北钉螺（Oncomelania hupensis）体内凝集素的提取方法及其凝集活性。方法用20%～100%硫酸铵对钉螺蛋白进行梯度分级沉淀,检测不同沉淀对兔红细胞的凝集活性。分别用2.5 mg/ml D-半乳糖、D-果糖、D-葡萄糖、蔗糖、麦芽糖和乳糖等6种糖溶液对有凝集活性的沉淀进行倍比稀释,测定其红细胞凝集活性的变化。并测定不同温度（25～90℃）和pH值（3.0～10.0）对钉螺凝集素凝集活性的影响。结果硫酸铵分级沉淀法提取钉螺凝集素时,20%～40%饱和梯度所得的沉淀具有较高的凝集活性。其凝集活性能被半乳糖和乳糖抑制。当pH值为7.0时钉螺凝集素活性最高。30～70℃水浴时,随温度的增加其凝集活性降低,高于80℃时无凝集活性。结论钉螺体内存在半乳糖和乳糖凝集素,其凝集活性受温度和酸碱度的影响。

英文摘要：

Objective To explore the extraction methods of agglutinin from Oncomelania hupensis snail and study its haemagglutination activity.Methods Protein obtained by ammonium sulfate fractionation precipitation with 20%-100% saturation of ammonium sulfate.Its haemagglutination activity was determined by rabbit erythrocytes.The precipit-ation which could agglutinate rabbit erythrocytes was diluted with 2.5 mg/ml D-galactose,D-fructose,D-glucose,saccharose,maltose and lactose,respectively,and then their haemagglutination activity was tested.Snail agglutinin were incubated at different temperatures（25-90 ℃） and assayed for agglutinating activity.The effect of pH on the haemagglutination activity was determined by using the PBS buffer at different pH values（3.0-10.0）.Results Oncomelania snail agglutinin exhibited high haemagglutination activity in 20%-40% saturated ammonium sulfate pellet.Lactose and galactose could inhibit the haemagglutination activity of snail agglutinin.The agglutinin showed maximum activity at pH 7.0.In temperature range of 30-70 ℃,the haemagglutination activity decreased with increasing temperature,and all activity lost beyond 80 ℃.Conclusion Galactose/lactose specific agglutinin exists in Oncomelania snail,its haemagglutination activity is affected by pH and temperature.