FUNCTIONAL-CHARACTERISTICS OF LYMPHOCYTES ISOLATED FROM THE RAT LARGE-INTESTINE - RESPONSE TO T-CELL MITOGENS AND NATURAL-KILLER CELL-ACTIVITY

Abstract

Using successive EDTA and collagenase treatments, 2 fractions of mucosal lymphocytes were isolated from the rat large intestine that differ in morphologic and functional characteristics. Intraepithelial lymphocytes consisted largely of granular lymphocytes (91 .+-. 6%) that did not respond to stimulation with phytohemagglutinin [PHA] or concanavalin A [Con A], but had natural killer cytotoxic activity against the YAC-1 [mouse lymphoma] cell line. The natural killer cytotoxicity of the intraepithelial lymphocytes was specifically reduced by the addition of increasing numbers of unlabeled homologous tumor cells but not by unlabeled thymocytes. The sensitivity of different target cell lines to lysis by intraepithelial lymphocytes was the same as splenocytes from the same rat strain. Lymphocytes from the lamina propria contained 21 .+-. 4% granular cells with the remainder being typical small lymphocytes. The lamina propria fraction responded well to stimulation with Con A, PHA and pokeweed mitogen, and also had natural killer activity against YAC-1 cells.