The phospholipase B content of the intestines of rats infected with varied larvae doses of Nippostrongylus brasiliensis.

Phospholipase B activity, bone marrow eosinophilia and worm burden were measured in separate groups of rats that received initial infections of 100, 400, 800, 1200, 2400, and 4800 Nippostrongylus brasiliensis larvae. The results indicated that as the numbers of larvae in the inocula were increased, the resulting higher worm burdens caused the development of earlier and more intense bone marrow eosinophilias and earlier and greater phospholipase B activities. The expulsion of the adult worms from the host was followed by equally rapid decreases in bone marrow eosinophilia and enzyme activity. It was found that as the number of intestinal adult worms was increased from low to large numbers, the degree of the inflammatory response changed from mild to severe. This suggests that the inflammatory response was responsible for the elevated phospholipase B levels.