ABSTRACT
Objective To study the killing effects of fractional proteins from Microtus fortis (Mf) serum on schistosomula of Schistosoma japonicum. Methods Mf serum proteins were separated into albumin and globulin by means of salt out of ammonium sulfamate. The globulin was then separated into 4 big and 12 small fractional proteins through Sephacryl S-300 column chromatography and electrophoresis elution. The killing effects were observed in vitro in cultivation in which the purified fractional proteins and schistosomula of S. japonicum were incubated together for 48 h. Results The mortality rate of schistosomula acted by Mf globulin was 59.2% and when added with complements was 68.4%. The killing effects of the 2nd and 3rd big fractional proteins were the same as that of Mf globulin. Three small fractional proteins (3.2, 3.3, 3.4) showed the higher killing effects which made the mortality rate of schistosomula 45.1%, 57.6% and 67.2%, respectively. The fractional protein of 100-135 kDa also showed the same killing effect as that of Mf globulin. Globulin from BALB/c mice sera had no significant effect on schistosomula. There was no significant difference in the mortality rate of schistosomula acted by both albumins. Conclusions Mf globulin has significant killing effects on schistosomula of S.japonicum in vitro and 100-135 kDa fractional protein may be an important effective molecule.