The Action of Bacterial Polysaccharides on Allergic Phenomena

Abstract

Polysaccharides (Ps) derived from cells of Proteus vulgaris or culture filtrates of this organism possess anti -allergic properties in doses which are by far inferior to those of other known anti-allergic drugs. They have no direct antihistamine or antiserotonin effect in vitro, nor do they counteract the effects of histamine aerosol in the intact animal. Their antiserotonin activity in the intact guinea pig exposed to serotonin aerosol is feeble. Under certain conditions they bind histamine in vitro, but do not cause any appreciable change in plasma histamine in anesthetised cats. Most of them are pyrogenic in the doses in which they afford protection against anaphylactic shock. However, some of them are non-pyrogenic in anti-anaphylactic doses; thus pyrogenicity is not a prerequisite of their anti-anaphylactic property, nor does their anti-allergic activity seem to be directly correlated with their effects on leucocytes. The only effect directly connected with the anti-anaphylactic action which we could find in our experiments was that the reactivity of the isolated gut taken from an animal treated with anti-anaphylactic doses of Ps, is greatly reduced when threshold concentrations of the antigen are used although it reacts normally towards histamine. The mechanism of this effect is unknown, but would seem to represent a new type of anti-anaphylactic action.