Ea. Deannystrom et Je. Samuel, AGE-RELATED RESISTANCE TO 987P FIMBRIA-MEDIATED COLONIZATION CORRELATES WITH SPECIFIC GLYCOLIPID RECEPTORS IN INTESTINAL MUCUS IN SWINE, Infection and immunity, 62(11), 1994, pp. 4789-4794
Strains of enterotoxigenic Escherichia coli that produce 987P fimbriae
(987P(+) strains) colonize the small intestines and cause diarrhea in
neonatal (<6-day-old) pigs but not in weaned pigs. However, 987P(+) E
. coli strains adhere in vitro to intestinal epithelial cells from pig
s of both ages. Two intestinal components, designated 987R and 987M, b
ind 987P fimbriae (987P) on Western blots (immunoblots). We examined b
rush borders (BB) and intestinal washes (IW) from pigs to determine if
they contain glycolipids which bind 987P. Total glycolipid extracts f
rom BB and IW of 4-week-old pigs were separated on thin-layer chromato
grams and overlaid with purified 987P. Bound 987P were detected with 9
87P-specific antiserum. 987P bound to at least one moiety in both BB a
nd IW glycolipids and also bound to several purified glycolipids, incl
uding gangliotetraosylceramide, lactosylceramide (CDH), sulfatide (SFT
), gangliotriaosylceramide, and galactosylceramide (listed in order of
decreasing affinity). Strain 987, but not the isogenic 987P(-) strain
I36, bound to these same glycolipids, indicating that the fimbriae co
ntain the adhesin required for binding to these lipids. Glycolipids ex
tracted from BB and IW isolated from 3- and 4-week-old pigs and from B
B isolated from 1-day-old pigs contained similar amounts of glycolipid
s like CDH and SFT that bound 987P. Finally, 987P bound to CDH, SFT, a
nd total BB glycolipids separated by sodium dodecyl sulfate-polyacryla
mide gel electrophoresis and transferred to Immobilon, and these glyco
lipids had mobilities similar to that of 987M. Thus, 987M may contain
987P-binding glycolipids. We hypothesize that glycolipid receptors for
987P, most likely CDH or SFT, in the mucus of older pigs bind 987P an
d inhibit 987P-mediated intestinal colonization by preventing the atta
chment of 987P(+) E. coli to 987P receptors on the intestinal epitheli
um.