Immunity to Ascaris suum. 3. The importance of the gut for immunity in mice.

Abstract

In one experiment mice were immunized by repeated oral inoculations with Ascaris suum eggs. Immune mice and controls were challenged in 2 ways, viz., orally with eggs and intravenously with in vitro hatched second-stage larvae of Ascaris suum. In a second experiment immune mice and controls were sacrificed 8 hrs after an oral challenge with eggs. It is concluded that the intestine is important for immunity against Ascaris suum, and that the defence mechanism is acting by interfering with the process of hatching and the larval penetration of the gut mucosa. It became evident from Experiment 1 that the large majority of the third-stage larvae detected in the lungs after oral challenge had not developed from second-stage larvae in the lungs, but was most likely coming from the liver.