Trichinella spiralis infection in mice. Mechanism of the resistance in animals genetically selected for high and low antibody production.

Mice genetically selected according to their capacity to produce antibody were orally infected with fifty muscle larvae. After 1 month, the number of larvae found in low responder mice was twice the number found in high responder mice. Following a second infection, low responder mice were completely protected while high responder mice showed only partial protection. It is suggested that the better resistance of high responder mice after a primary infection is due to their high and rapid antibody production. However, at the time of a secondary infection both lines of mice possess enough antibody to act on the effector cells (macrophages, eosinophils, etc.) and resistance is then dependent on the metabolic activity of these cells, which is more intense in the low responder mice.