REGULATION OF MHC MOLECULES ON MBP POSITIVE OLIGODENDROCYTES IN MICE BY IFN-GAMMA AND TNF-ALPHA

The expression of class I and class II histocompatibility antigens by myelin basic protein (MBP)-positive oligodendrocytes, in response to exogenous cytokines, has been investigated in vitro. It has been found that interferon-gamma (IFN-gamma), although capable of class I induction, does not induce class II on oligodendrocytes. Furthermore, tumour necrosis factor-alpha (TNF-alpha), which was shown to induce class I MHC on other neural cells, failed to induce class I on oligodendrocytes. A combination of IFN-gamma and TNF-alpha also failed to facilitate the expression of class II antigens on oligodendrocytes, nor did it amplify the expression of class I seen with IFN-gamma alone. Thus it appears that MBP+ murine oligodendrocytes are refractory to class II induction, and express class I in response to IFN-gamma but not TNF-alpha. The differential regulation and class of MHC expression may have implications in terms of the initiation and targeting of immune responses directed toward the oligodendrocyte.