Monocyte chemoattractant activity associated with human colon mucosal cells

Abstract

Mucosal epithelial cell preparations from 18 disease-free segments of human colon resections and 7 cell lines were examined for chemoattractant properties. Mucosal cells were dissociated from lamina propria by sequential incubations in ethylenediaminetetraacetic acid, harvested at 1.5 x 10(6) cells/ml, and lysed. Lysates were tested for chemoattractant activity for monocytes and neutrophils. Chemoattractant preparations were further purified by gel filtration chromatography, and amino acid analysis was performed on selected chemoattractant fractions. Mucosa from normal bowel exhibited significant chemoattractant properties for monocytes, up to 15 times greater than for neutrophils. Checkerboard analysis indicated chemotaxis rather than chemokinesis. Neither cell culture nor lamina propria cell lysates exhibited statistically significant chemoattraction, although activity was evident in certain preparations of isolated cell cultures. Chromatography of human mucosal chemoattractant preparations consistently gave peaks of activity in the 2000 dalton range. These yielded consistent amino acid profiles, with aspartic acid, glutamic acid, glycine, alanine, and lysine being dominant in all preparations. This peptide is apparently different from other known chemotactic agents and could play a role in recruitment of mononuclear phagocytes to the mucosa of the human colon.