E C Ebert1. 1. Department of Medicine, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, USA.
Abstract
BACKGROUND & AIMS: Inflammation is created by the movement of leukocytes toward soluble attractants (chemokines). The aim of this study was to identify the chemokines that attract intestinal lymphocytes. METHODS: Intraepithelial and lamina propria lymphocytes were isolated from human jejunal mucosa of healthy individuals and cultured in interleukin (IL) 2 for 3 days. Migration was assessed using the Boyden transwell assay. Increases in cytoplasmic calcium ion concentration ([Ca2+]i) were measured from changes in fluorescence in Fura-2-loaded lymphocytes on exposure to the cytokines. RESULTS: A large number of intraepithelial lymphocytes migrated toward IL-8 and RANTES (regulated on activation, normal T cell expressed and secreted), and a small number migrated toward IL-10. In contrast, only a few lamina propria lymphocytes migrated toward IL-8, and none responded to the other chemokines tested. The chemokines IL-8 and IL-10, but not RANTES, increased [Ca2+]i in intraepithelial lymphocytes; this calcium mobilization was not affected by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, indicating that calcium is released from intracellular sources. None of the factors caused calcium mobilization by lamina propria lymphocytes. CONCLUSIONS: This study shows that intraepithelial lymphocytes have greater migratory and calcium-mobilizing activity than lamina propria lymphocytes and that these two activities do not correlate with each other.
BACKGROUND & AIMS: Inflammation is created by the movement of leukocytes toward soluble attractants (chemokines). The aim of this study was to identify the chemokines that attract intestinal lymphocytes. METHODS: Intraepithelial and lamina propria lymphocytes were isolated from human jejunal mucosa of healthy individuals and cultured in interleukin (IL) 2 for 3 days. Migration was assessed using the Boyden transwell assay. Increases in cytoplasmic calcium ion concentration ([Ca2+]i) were measured from changes in fluorescence in Fura-2-loaded lymphocytes on exposure to the cytokines. RESULTS: A large number of intraepithelial lymphocytes migrated toward IL-8 and RANTES (regulated on activation, normal T cell expressed and secreted), and a small number migrated toward IL-10. In contrast, only a few lamina propria lymphocytes migrated toward IL-8, and none responded to the other chemokines tested. The chemokines IL-8 and IL-10, but not RANTES, increased [Ca2+]i in intraepithelial lymphocytes; this calcium mobilization was not affected by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, indicating that calcium is released from intracellular sources. None of the factors caused calcium mobilization by lamina propria lymphocytes. CONCLUSIONS: This study shows that intraepithelial lymphocytes have greater migratory and calcium-mobilizing activity than lamina propria lymphocytes and that these two activities do not correlate with each other.