Interleukin-1 beta decreases HLA class II expression on a glioblastoma multiforme cell line.

ABSTRACT

Antigens encoded within the major histocompatibility complex (MHC) are not normally expressed in the central nervous system (CNS), but can be induced by treatment with interferon-gamma (IFN-gamma). Other cytokines released during an inflammatory process can potentially influence MHC expression as well. One cytokine of interest is interleukin-1 (IL-1), an immunoregulatory polypeptide that is produced by macrophages and also by cells in the CNS. In this study, the effect of IL-1 beta on MHC expression in a human glioblastoma multiforme cell line, U-105 MG, has been examined. Treatment of U-105 MG with 10 U IL-1 beta/ml for a period of 5 days resulted in a decrease in constitutive cell surface HLA class II expression and limited the induction of class II by IFN-gamma. This effect was also observed on steady-state levels of class II RNA and could be neutralized with antibodies to IL-1 beta. All class II transcripts examined (HLA-DR, -DQ, and -DP alpha and beta) were affected. Class I expression was only marginally changed by IL-1 beta treatment. A minimal concentration of 1 U IL-1 beta/ml was required to reduce class II expression and a kinetics experiment indicated that U-105 MG must be treated for at least 4 days with IL-1 beta for a decrease in class II expression to be observed. This study suggests that IL-1 may play a role in limiting immunoreactivity in the CNS by limiting class II induction.