Suppression of IgE responses by antigen inhalation: failure of tolerance mechanism(s) in newborn rats.

The natural response of immunocompetent adult animals to antigen inhalation is the development of T-lymphocyte mediated tolerance, particularly in the IgE-antibody class (Holt & Sedgwick, 1987). It has been suggested that this process functions as a protective mechanism to limit sensitization to aeroallergens. In the present report, it is shown that the inhalation tolerance process does not function during the early postnatal period, and the lack of this protective mechanism may contribute to the increased risk of allergic sensitization during infancy. These experiments also demonstrate that adoptive transfer of adult splenocytes to newborns confers adult capacity for tolerance development, which suggests that delayed maturation of certain T-cell subset(s) may underly this transfer defect.