FUNCTIONAL DIFFERENCES BETWEEN HEPATOCYTES AND BILIARY EPITHELIAL-CELLS IN HANDLING POLYMERIC IMMUNOGLOBULIN A2 IN HUMANS, RATS, AND GUINEA-PIGS

Citation
S. Sakisaka et al., FUNCTIONAL DIFFERENCES BETWEEN HEPATOCYTES AND BILIARY EPITHELIAL-CELLS IN HANDLING POLYMERIC IMMUNOGLOBULIN A2 IN HUMANS, RATS, AND GUINEA-PIGS, Hepatology, 24(2), 1996, pp. 398-406
Citations number
46
Categorie Soggetti
Gastroenterology & Hepatology
Journal title
ISSN journal
02709139
Volume
24
Issue
2
Year of publication
1996
Pages
398 - 406
Database
ISI
SICI code
0270-9139(1996)24:2<398:FDBHAB>2.0.ZU;2-1
Abstract
Immunoglobulin A (IgA) in bile plays an important role in preventing t he biliary tract from infection, In the present study, to clarify the functional differences between hepatocytes and biliary epithelial cell s (BEG) in handling polymeric IgA2 (pIgA2), the major and important Ig A in bile, we have determined in different species the binding charact eristics of I-125-labeled pIgA2 to tissue sections of human, rat, and guinea pig livers. We have also examined the binding and transport fea tures of I-125-labeled and gold-labeled pIgA2 in cultured hepatocytes and cultured BEC of rat and guinea pig. Asialofetuin, an asialoglycopr otein, or an antisecretory component antibody was used for determining the binding characteristics of pIgA2 to the cells. Grains of I-125-pI gA2 were morphometrically analyzed. In tissue sections, I-125-pIgA2 wa s predominantly bound to Pat hepatocytes as well as to human and guine a pig BEG. The binding of I-125-pIgA2 to the cells was significantly i nhibited by pretreatment with an antisecretory component (SC) antibody (P < .001), but not by preloaded asialofetuin. In cultured cells, lab eled pIgA2 was observed binding predominantly to rat hepatocytes and g uinea pig BEC as compared with fat BEC and guinea pig hepatocytes (bot h P < .001), respectively, and gold particles of gold-labeled pIgA2 we re localized in the tubulovesicular structures and biliary luminal spa ces of those cells, These results suggested that pIgA2 was bound selec tively to hepatocytes in the rat liver, and to BEC hr the human and gu inea pig livers, through the SC but not through an asialaglycoprotein receptor, sued was transported transcellularly and secreted into bile.