The chemiluminescence of cyprinid leucocytes in response to zymosan and extracts of Ligula intestinalis (Cestoda)

The chemiluminescent response to roach and gudgeon pronephric leucocyteswas investigated following exposure to zymosan and extracts from Ligula intestinalis. Cells from both fish species produced chemiluminescence in response to zymosan which was enhanced by opsonisation with fish serum and addition of parasite extracts. Neutrophils and L1 granulocytes from roach were shown to phagocytose zymosan particles. Leucocytes exposed to parasite extracts alone varied in their response with only gudgeon cells producing a chemiluminescent response. The significance of this differential activation of host leucocytes by Ligula extracts is discussed with reference to the interaction of the parasite and host cells in vivo.