At. Mariassy et al., EFFECT OF ANTIGEN ON THE GLYCOCONJUGATE PROFILE OF TRACHEAL SECRETIONS AND THE EPITHELIAL GLYCOCALYX IN ALLERGIC SHEEP, Journal of allergy and clinical immunology, 93(3), 1994, pp. 585-593
To characterize the glycoconjugate composition of tracheal secretions
and the apical glycocalyx of the tracheal epithelium under baseline co
nditions and after antigen challenge, sheep allergic to Ascaris suum w
ere intubated with a double-balloon nasotracheal tube to create a trac
heal chamber. After an initial tracheal lavage, the animals were eithe
r exposed to intratracheally nebulized phosphate-buffered saline (PBS)
(3 ml, n = 6) or A. suum antigen (251,000 protein nitrogen units in 3
ml of PBS, n = 6). Tracheal lavage was repeated 2 hours later, and th
e animals were killed. An enzyme-linked lectin assay and lectin histoc
hemical analysis were used to characterize carbohydrate residues in ly
ophilized, resuspended tracheal secretions and the apical glycocalyx o
f the tracheal epithelium, respectively. Eight lectins were used to de
tect GalNAc, alpha-Gal, beta-Gal, alpha-Fuc, (1-3)Man, alpha-Man/Glu,
alpha-Man, and alpha-(2-3)sialyl residues. The amounts of total nondia
lyzable solids, proteins, and lipids in tracheal secretions were appro
ximately twice as high after exposure to A. suum than after exposure t
o PBS. All carbohydrate residues were present in tracheal secretions a
fter exposure to PBS and A. suum, but the reactivity was higher after
exposure to A. suum for beta-Gal (+125%), alpha-Man/Glu (+150%), alpha
-(1-3)Man (+287%), alpha-(2-3)sialyl (+353%), and alpha-Man (+448%) (p
< 0.05). Likewise, the apical glycocalyx contained all carbohydrate r
esidues after exposure to PBS and A. suum; afer exposure to A. suum, t
he reactivity was greater for alpha-GalNAc (+18%), alpha-(2-3)sialyl (
+90%), beta-Gal(1-3)GalNAc (+433%), and alpha-(1-3)Man (+482%) (p < 0.
05). There were no differences in other carbohydrate residues in eithe
r tracheal secretions or the apical glycocalyx. These antigen-induced
changes in the respective glycoconjugate profiles of tracheal secretio
ns and the apical glycocalyx of the tracheal epithelium could have an
effect on airway defenses, including bacterial adhesion to the epithel
ium.