Differential effects of beta and gamma interferons on expression of major histocompatibility complex antigens and intercellular adhesion molecule-1 in cultured fetal human astrocytes.

We investigated the modulatory effects of human interferon beta (IFN-beta) and gamma (IFN-gamma) on expression of class I and II major histocompatibility complex (MHC) antigens and intercellular adhesion molecule-1 (ICAM-1) in fetal human astrocytes in culture using flow cytometry and immunocytochemistry. Under the baseline condition, class I MHC antigen and ICAM-1 were expressed in a moderate number (23 to 76%) of astrocytes, whereas class II MHC antigen was expressed in only a small number (0.3 to 8%) of astrocytes. Following a 72-hour treatment with IFN-gamma (10 to 100 U/ml), expression of all three antigens increased greatly. Expression of class I MHC antigen was also elevated by exposure to IFN-beta (10 and 100 IU/ml). However, IFN-beta did not significantly induce expression of class II MHC antigen or ICAM-1. Furthermore, IFN-beta significantly reduced IFN-gamma-induced expression of class II MHC antigen but not of class I MHC antigen or of ICAM-1. The differential effects of IFN-beta and IFN-gamma on expression of class I and II MHC antigens and ICAM-1 in fetal human astrocytes suggest that interferons serve as modulators of astrocyte function at sites of inflammation in the human CNS.