Absorption of antigens after oral immunisation and the simultaneous induction of specific systemic tolerance.

Antigenic proteins may be absorbed intact. We report here results from in vivo experiments in mice showing that the prior feeding of protein antigen may reduce the subsequent absorption of that antigen without altering its elimination from the circulation. This may be a function of local immunity. We have also shown that the same feeding regime can paradoxically induce a state of systemic tolerance and suggest that the two phenomena contribute to the safe handling of these antigens.