THE STEROID-HORMONE DEHYDROEPIANDROSTERONE (DHEA) BREAKS INTRANASALLYINDUCED TOLERANCE, WHEN ADMINISTERED AT TIME OF SYSTEMIC IMMUNIZATION

The induction of intranasal tolerance might be dependent on specific c haracteristics of mucosal, nose-draining lymph nodes. Such a specific characteristic might lie in the metabolism of the steroid hormone DHEA . Conversion of the prohormone DHEAS into DHEA is dependent on DHEAS-s ulphatase activity in lymph nodes. This activity is low in mucosa-drai ning lymph nodes compared to peripheral lymph nodes, leading to differ ences in microenvironment. However, administration of DHEA before the induction of intranasal tolerance, could not change tolerance inductio n. We next determined the effect of DHEA after the induction of intran asally induced tolerance and demonstrated that the steroid hormone and some of its derivatives are able to break tolerance, when administere d at time of systemic immunization. These findings might have implicat ions for the regulation of intranasal tolerance and the use of DHEA. ( C) 1998 Elsevier Science B.V. All rights reserved.