The use of hapten-polysaccharide conjugates for the induction of B-cell tolerance involving IgE responses. II. Specific tolerance induced by sulphonamide-substituted levan in the mouse.

Normal and sulphonamide-sensitised mice were made tolerant with 4-sulphanilamido-benzoic-diaminopropyl-carboxymethyl-levan (4-SABA-Le). The tolerance was demonstrably specific for the sulphanilamide moiety of the hapten and extended to related compounds sharing this determinant. Mice sensitised with a 4-SABA-chicken gamma-globulin conjugate developed fatal anaphylactic shock after the injection of sulphanilamide or 4-SABA-ovalbumin, whereas allergic mice subsequently tolerised with 4-SABA-Le did not. The tolerance induced was long lasting since mice were still tolerant 7 months after an injection of an optimal dose of tolerogen. Suppressor cells play little or no part in the maintenance of this unresponsive state since even a 10-fold excess of splenic cells from tolerant animals failed to inhibit the responsivenss of 4-SABA-primed cells when they were transferred together into irradiated recipients.