RAT INTESTINAL EPITHELIAL-CELLS PRESENT MAJOR HISTOCOMPATIBILITY COMPLEX ALLOPEPTIDES TO PRIMED T-CELLS

Background/Aims: Intestinal epithelial cells present protein antigens to primed T cells in vitro. The aim of this study was to investigate w hether intestinal epithelial cells present peptide antigens in vitro a nd in vivo after oral administration. Methods: Small intestinal epithe lial cells from naive LEW (RT1') rats pulsed in vitro with a synthetic immunogenic major histocompatibility complex allopeptide, RT1.D-u bet a 20-44, or in vivo by oral administration of the peptide were tested for their ability to induce specific proliferation of LEW T cells prim ed in vivo to RT1.D-u beta 20-44. Results: In vitro pulsed intestinal epithelial cells induced specific proliferation of RT1.D-u beta 20-44- primed T cells. Intestinal epithelial cells isolated from LEW rats tha t received a single oral dose of RT1.D-u beta 20-44 18 hours earlier a lso induced specific proliferation of RT1.D-u beta 20-44-primed LEW T cells. Furthermore, epitheliaI cells harvested from LEW rats that rece ived WF (RT1(u)) splenocytes orally 18 hours earlier induced specific proliferation of RT1.D-u beta 20-44-primed LEW T cells. Conclusions: I ntestinal epithelial cells take up processed alloantigen in vitro and in vive for presentation as peptides to primed T cells. These observat ions provide a novel approach to study the role of the intestinal immu ne system in immune regulation in vivo.