Dogs may be immunized against lethal doses of the duodenal loop poison by means of small doses of the loop fluid from dog or cat and by material obtained from human cases of intestinal obstruction. The immunity is transient and may disappear within a few weeks.
Dogs immunized by repeated doses of loop fluid show a definite resistance against the intoxication of a closed duodenal loop and may survive twice the usual period.
A dog that recovers from simple intestinal obstruction may possess a strong resistance to the intoxication of a closed duodenal loop, thus indicating a similar type of intoxication in the two conditions.
The sera of immune dogs are inactive when incubated with duodenal loop fluid.
The organ extracts and emulsions (liver, spleen, lung) of immune dogs rapidly destroy the loop poison during incubation in vitro.
This destructive property is possessed by a clear filtrate of the digested immune organs, excluding adsorption, and is lost after long periods of incubation (twelve weeks).
We are investigating the action of this immune organ extract to determine whether it can destroy the closed-loop poison in vivo and perhaps be of value in treatment.