Mucosal immune response to an antigen leads to a state of attenuated system
ic response to the same antigen, known as mucosal or oral tolerance. Thus,
autoantigen administration via mucosal routes could be useful in the preven
tion of autoimmune diseases. Although in various models of autoimmune disea
se it is often effective, in some cases it is ineffective and in other case
s even harmful. In these cases it is likely that, concomitantly with tolera
nce, a productive immune response is induced that exacerbates autoimmunity.
Recent evidence suggests that induction of cytotoxic T lymphocytes capable
of destroying pancreatic beta cells may be an unavoidable consequence of m
ucosal administration of pancreatic beta-cell associated autoantigen. To im
prove the safety and efficacy of mucosal tolerance induction in the prevent
ion of type 1 diabetes, further means to control the induction of cytotoxic
T lymphocytes and other potentially tissue-destructive immune effectors ma
y be required.