Induction of anti-secretory factor in mice by the nonintestinal parasite Schistosoma mansoni.

Anti-secretory factor (ASF) was determined by the rat intestinal loop model in the pituitary gland and in the blood at various intervals after experimental infection of mice with Schistosoma mansoni. ASF could be detected in the pituitary gland by 6 hr after percutaneous infection with cercariae and in the blood at 24 hr after infection. A peak level was reached 3 days after infection and, after a decline, 2 more peaks were noted between 4 and 8 wk after infection. Characterization of ASF induced by S. mansoni by means of isoelectric focusing revealed 2 distinct peaks at approximately pH 4 and pH 5, respectively. Upon affinity chromatography on agarose, the activity dissociated in a gradient of methyl-alpha-D-glucoside at 1.0 M but not at 0.1 or 0.3 M concentrations.