ACTIVATION AND MIGRATION OF CD8 T-CELLS IN THE INTESTINAL MUCOSA

The activation of CD8 T cells was studied using transgenic mice expres sing an MHC class I-restricted OVA-specific TCR (OT-I), Immunization o f OT-l mice resulted in activation of lymph node T cells and up-regula tion of expression of B220, CD11a, and CD44 and caused a preferential loss of mucosal-type T cells from the periphery, Immunization induced dramatic changes in intestinal lymphocytes, including the appearance o f a CD11a high population that resembled peripheral T cells and induce d a primary cytolytic response, Activation of adoptively transferred O T-l cells induced migration of CD8 T cells into the lamina propria and intraepithelial lymphocyte compartments, The results suggest that Ag presentation in the intestinal epithelium occurs, and that CD8 cells a ctivated in the periphery can readily enter the mucosa during an ongoi ng immune response.