Induction of Ia antigens on thyroid cultures by syngeneic T lymphocytes: a model of autoimmune disease.

We previously reported that the expression of Ia antigens on cultured monolayers of murine thyroid epithelial cells (TEC) occurred with a particular distribution exclusively on the basal part of the cultured thyroid cells, while class I antigens of the major histocompatibility complex (MHC) are only detected on the apical surface. It appears that deposition of syngeneic lymphocytes induces, 24 h later, Ia expression on the apical side of cultured TEC, the surface that is in direct contact with the responder lymphocytes during syngeneic sensitization of T lymphocytes. We hypothesized that this phenomenon could represent, in syngeneic situations, the restriction process in antigen recognition by T cells, as demonstrated by Ia restricted primary syngeneic sensitization (PSS) on murine TEC.