TIME-DEPENDENT ALTERATIONS OF 3-FUCOSYL-N-ACETYL-LACTOSAMINE (CD15) EXPRESSION IN THE ENDOLYMPHATIC SAC OF ADULT GUINEA-PIGS AFTER GLYCEROLADMINISTRATION

The present study examined the effect of glycerol administration on 3- fucosyl-N-acetyl-lactosamine (CD15) epitope expression in the endolymp hatic sac (ES) of the guinea pig's inner ear. Adult guinea pigs were i njected intravenously with glycerol (2 g/kg body wt.). CD15 expression was studied at 80 min up to 5 h after treatment. In untreated animals single cells and cell groups in the ES expressing CD15 epitope intra- and intercellularly were identified by immunohistochemistry to be mai nly in the epithelial layer of the rugosal and distal part of the sac. Glycerol administration modulated the expression of CD15 epitope. In the epithelial layer, expression decreased and was nearly depleted aft er 3 h. After 4 h of glycerol administration, CD15 expression reappear ed and reached the comparable level of controls. The numbers of CD15-p ositive cells in the lumen of the ES increased steadily and arrived at their the highest levels in 2-h specimens. The localization of CD15-e pitope expression and its modulation after glycerol administration wit hin the ES implies that this molecule may play a role in re-establishi ng the sac's normal function. In addition, we speculate that CD15 may be associated with processes of an immune response in the inner ear.