Abstract: 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 precipitation 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.

Key words: Oncomelania hupensis, Agglutinin, Extraction, Haemagglutination activity