CHOLERA-TOXIN B-SUBUNIT - AN EFFICIENT TRANSMUCOSAL CARRIER-DELIVERY SYSTEM FOR INDUCTION OF PERIPHERAL IMMUNOLOGICAL-TOLERANCE

Oral administration of antigens, including allergens and autoantigens, may be an efficient way to prevent diseases associated with untoward immune responses to self- and non-self-antigens. However, this approac h has met with limitations because it usually requires repeated admini strations of large doses of antigen and is less efficient in an alread y immune host, and the effect is of short duration. We report that a s ingle oral administration of minute amounts of particulate or soluble antigen coupled to the B subunit of cholera toxin (CTB) can markedly s uppress systemic immune responses in naive and in systemically immune animals. Both early (2-4 hr) and late (24-48 hr) delayed type-hypersen sitivity reactivities were strongly suppressed. after feeding a single dose of CTB-conjugated antigen. Serum antibody responses were also de creased, although moderately, after oral administration of CTB-conjuga ted antigen. This strategy of tolerance induction, based on oral admin istration of small amounts of antigens conjugated to a mucosa-binding molecule, may find dread applications for preventing or abrogating unt oward immune responses.