Inhibition of Theiler's encephalomyelitis virus (GDVII strain) of mice by an intestinal mucopolysaccharide. I. Biological properties and mechanism of action.

A mucopolysaccharide has been obtained from intestinal tissue of adult mice which inhibits both infectivity and hemagglutination of Theiler's GDVII strain of encephalomyelitis virus of mice. The inhibitor is inactive against the FA and TO strains of Theiler's virus and against the Lansing strain of poliomyelitis virus. In the adult mouse, large amounts of the inhibitor are found only in the small intestine. The small intestine of infant mice, however, contains a considerably smaller amount of inhibitor. Inhibition, both in vivo and in vitro, appears to be the result of an interaction between virus and inhibitor. The intestines of man, monkey, rabbit, rat, cotton rat, hamster, sheep, cow, and pig contain relatively little inhibitor whereas guinea pig intestine contains as much as adult mouse intestine. An enzyme was found in the feces of mice, and several other animals, which is capable of destroying the inhibitory activity of the mucopolysaccharide with the liberation of reducing sugars.