Macrophages in protective immunity to Hymenolepis nana in mice.

When mice were treated with carrageenan just before infection with eggs of Hymenolepis nana, they failed to exhibit sterile immunity to the egg challenge, with evidence of a decrease in the number of peripheral macrophages (Mø) and the rate of carbon clearance. Although there were high levels of interleukin-1 (IL-1) released into the intestinal tracts of the parasitized mice at challenge infection, there was almost no release of IL-1 in those treated with carrageenan just before challenge. These results strongly suggest that Mø have an important role in protective immunity to H. nana in mice.