ANTI-GAMMA-DELTA T-CELL ANTIBODY BLOCKS THE INDUCTION AND MAINTENANCEOF ORAL TOLERANCE TO OVALBUMIN IN MICE

The oral administration of antigens is one of the means of inducing to lerance in adult mammals. In this report, the role of gamma delta T ce lls in the induction and maintenance of orally-induced tolerance to ov albumin was investigated. The injection of a monoclonal anti-gamma del ta T cell monoclonal antibody blocked the induction of oral tolerance, because the secondary immune responses to ovalbumin in these animals were comparable to the corresponding responses in ovalbumin-immunized control mice. Furthermore, depletion of gamma delta T cells either in vivo or in vitro abolished already established oral-tolerance. The fac t that the state of tolerance could be adoptively transferred to naive recipients by CD3(+)alpha beta(-)gamma delta(+) spleen cells from tol erant mice. These results suggest that systemic oral tolerance is indu ced and actively maintained by mechanisms involving gamma delta T cell s.