The delta-opioid receptor participates in T-cell development by promoting negative selection

The delta-opioid receptor-1 (DOR-1) as well as delta-opioid enkephalin peptides are expressed during maturation of T cells, although the functional significance of their expression remains unclear. Based on results which show that the administration of the highly selective delta-opioid agonist D-Pen2, D-Pen5]enkephalin (DPDPE) induces an altered pattern of T-cell differentiation in fetal thymic organ culture (FTOC), we hypothesized that DOR-1 is involved in the negative selection process. Our results show that superantigen-induced clonal deletion is promoted by DPDPE and significantly impaired in DOR-1-deficient mice. These results suggest that delta-opioids may play a homeostatic role in the negative selection process during T-cell development.