Abstract: | To investigate the immune environment of the peritoneal cavity, ICAM‐1 (intercellular adhesion molecule) expression on the apical surface of the hepatic peritoneum of LPS (lipopolysaccharide) stimulated rats was anlayzed ultrastructurally and chronologically with immnunoTEM&SEM. ICAM‐1 expression was restricted to the side of microvilli of the mesothelial cells. Microvilli demonstrated bulbous tips and included fuzzy coats and strands. Bulbous tips sometimes expressed the antigen, but fuzzy coats and strands did not. Intervillar cell surfaces lacked its expression. Although ICAM‐1 expression increased eightfold 24 hr after stimulation, the selective expression remained unchanged. These results suggest that microvilli are closely associated with cell migration in the peritoneal cavity through adhesion molecules that establish a road for migration. Clin. Anat. 12:20–26, 1999. © 1999 Wiley‐Liss, Inc. |