Impaired delayed hypersensitivity in germ-free guinea-pigs

Abstract

The delayed-type hypersensitivity response of germ-free guinea-pigs was found to be defective. Whereas almost all conventionally reared guinea-pigs became hypersensitive to an allergenic hapten (picryl chloride), most germ-free guinea-pigs did not. When injected with a fully antigenic substance, bovine γ-globulin (BGG), none of the germ-free animals acquired BGG-specific delayed hypersensitivity. Further, none of the germ-free guinea-pigs developed spontaneous iso-hypersensitivity for a beta globulin as do conventional guinea-pigs. In addition, germ-free guinea-pigs given Freund's complete adjuvant did not develop the characteristic induration or erythema normally seen at injection sites and most animals died within 21 days.

Germ-free guinea-pigs given competent lymphoid cells from highly sensitized conventional guinea-pigs were unable to translate adoptive hypersensitivity into delayed dermal reactions.

A permeability factor in aged guinea-pig sera, injected into the skin of germ-free and conventional animals to determine whether the skin of germ-free guinea-pigs was able to support reactions, initiated immediate dermal reactions of equal intensity in both sets of animals.