A comparative study of eosinophil chemotactic factors was carried out
using cysticercoids and oncospheres of Hymenolepis nana. Cysticercoids
showed twice the chemotactic activity for eosinophils than the oncosp
heres. Eosinophilia induced by oncospheres and cysticercoids observed
in secondary and primary infections, respectively were discussed from
the view point of the immunobiology of this parasite.