Attachment of mouse neutrophils in vitro on praziquantel-damaged surface of adult Schistosoma japonicum in the presence of immune sera

Attachment of mouse neurtrophils (Neu) in vitro on praziquantel-damaged surface of adult Schistosoma japoncium in the presence of 3 culture systems (NS-CHN, IS-CHN or ASE-CHN), consisting of 1) normal rabbit serum (NS), infected rabbit serum (IS) or rabbit antisera to freeze-thawed tegument exudates of adult worms (ASE); 2) glycogen-activated mouse peritoneal Neu (N); 3) guinea pig serum served as complement (C) and 4) Hanks’ balanced salt solution (H), were studied. When male and female worms were maintained in IS-CHN or ASE-CHN containing praziquantel 1 microg/mL for 2-20 h, or the worms were exposed to the drug 30 microg/mL for 4 h then transfected to the cluture system. Neu adhered to the damaged surface of the worms were seen. The attachment of Neu accentuated the tegument injury and resulted in worm death within 24 h. If immune serum was replaced by normal rabbit serum, no such phenomenon was seen. These results were confirmed by scanning electron microscopy.