Products of enteropathogenic e. coli inhibit lymphokine production
by gastrointestinal lymphocytes.
Klapproth, Jan-Michael, Michael S. Donnenberg, John M. Abraham,
Stephen P. James.
Department of Medicine, School of Medicine, University of Maryland
at Baltimore and Baltimore VA Medical Center, Baltimore, MD 21201
APStracts 3:0110G, 1996.
Previously we have shown that lysates of enteropathogenic E. coli
(EPEC) inhibit lymphokine production by mitogen activated peripheral
blood mononuclear cells. The aim of the present study was to
determine whether products of EPEC alter lymphokine expression by
gastrointestinal mucosal lymphocytes. Lysates from EPEC clones
inhibited mitogen-stimulated IL-2, IL-4, IL-5, and interferon-gamma
but not IL-8 mRNA expression by lamina propria mononuclear cells
isolated from surgically resected colon specimens. Inhibitory lysates
did not significantly change CD25 expression on either CD4, CD8 or
CD45R0 lymphocytes by flow cytometry. Bacterial supernatants of EPEC
inhibited IL-2 and IL-5 protein secretion by mitogen-stimulated
PBMCs. EPEC lysates inhibited IL-2 mRNA expression induced by lysates
of nonpathogenic E. coli. In conclusion, EPEC contains a novel
gene(s) that encode factors that selectively inhibit IL-2, IL-4, IL-5
and interferon-gamma expression by mucosal mononuclear cells without
affecting CD25 or IL-8 expression. Thus, enteric bacteria can produce
factors that may regulate the function of the gastrointestinal
mucosal immune system.
Received 18 July 1995; accepted in final form 14 May 1996.
APS Manuscript Number G300-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 17 June 96