IDENTIFICATION OF NEUROTENSIN-RELATED PEPTIDES IN HUMAN THYMIC EPITHELIAL-CELL MEMBRANES AND RELATIONSHIP WITH MAJOR HISTOCOMPATIBILITY COMPLEX CLASS-I MOLECULES

This study shows the expression at the cell surface of human thymic ep ithelial cells (TEC) of a neurotensin (NT)-like immunoreactivity. NT r adio-immunoassay (RIA) revealed that cultured human TEC contain +/-5 n g immunoreactive (ir) NT/10(6) cells, of which 5% is associated with p lasma cell membranes. HPLC analysis of NT-ir present in human TEC show ed a major peak of NT-ir corresponding to NT1-13. NT-ir was not detect ed in the supernatant of human TEC cultures. Using an affinity column prepared with a anti-MHC class I monoclonal antibody, NT-ir-related pe ptides were retained on the column and eluted together with MHC class I-related proteins. According to the elution time on HPLC of these pep tides, they correspond to intact NT1-13, as well as to smaller fragmen ts of NT1-13.