In Vivo Proliferation of T and B Lymphocytes in the Epithelium and Lamina Propria of the Small Intestine

Abstract

Intraepithelial lymphocytes (IEL) and lymphoid cells in the lamina propria (LPL) of the gastrointestinal (GI) tract are effector or regulator cells for an effective mucosal immune response. Little is known about the proliferation of lymphocytes in these compartments.¹ The thymidine analog bromodesoxyuridine (BrdU) is incorporated during the DNA synthesis of the cell cycle. BrdU can easily be detected using an immunocytological double stain for incorporated BrdU and lymphocyte subsets. This method was used to determine the proliferation of lymphocyte subsets within IEL or LPL suspensions from the jejunum and ileum. During the purification of the isolated IEL and LPL, high numbers of cells are often lost. Therefore in the present study the suspensions were analyzed without further purification steps.