We analyzed whether normal human hepatocytes, which normally do not display Class I1 major histocompatibility complex antigens, can be induced to express them in vitro, and whether this induction has an in vivo counterpart in chronic liver diseases. While both a-and y-interferon induced expression of Class I antigens, only y-interferon induced expression of Class I1 antigens on hepatocytes in vitro. Recombinant interleukin 2 had no effect on major histocompatibility complex antigen expression. Both Class I and Class I1 antigens could be detected by indirect immunofluorescence on hepatocytes from patients with various forms of chronic liver disease, regardless of etiology. These findings suggest that y-interferon produced by T lymphocytes that infiltrate the liver during the course of chronic hepatitis induces Class I1 major histocompatibility complex antigen expression and may endow the hepatocytes with the capacity to perform accessory (antigen-presenting) cell β¬unctions.
The development of monoclonal antibodies to monomorphic determinants of Class I1 major histocompatibility complex (MHC) antigens has allowed a detailed analysis of their normal tissue distribution (1, 2).
Previous studies have shown that these cell surface glycoproteins have a broader tissue expression than originally suggested, as they are also present on cells which are usually not associated with the immune response (3) and may show variability in expression among different individuals and can be newly induced by various stimuli (4-8). Furthermore, the expression of Class I1 MHC antigens in nonlymphoid cells seems to enable the cells to perform accessory cell functions (9-ll), thus indicating that cells of different histotype can participate in the afferent limb of the immune response. In the present study, we analyzed whether normal hepatocytes, which normally lack detectable levels of Class I1 molecules, can be induced to express these antigens in uitro and whether this induction has an in uiuo counterpart in chronic liver disease.
Methods
Normal human hepatocytes were obtained from five patients who underwent surgical liver biopsy for Cell Cultures.