EXPRESSION OF INTERFERON-GAMMA RECEPTORS ON MURINE OLIGODENDROCYTES AND ITS REGULATION BY CYTOKINES AND MITOGENS

Interferon-gamma (IFN-gamma) is a cytokine known to exert an important immunological role on astrocytes and oligodendrocytes. As a receptor for IFN-gamma, has been demonstrated on murine astrocytes, we have sea rched for a specific receptor on the cell surface of pure mouse oligod endrocytes maintained in tissue culture. Using recombinant murine IFN- gamma labelled with I-125, We have established the basic physicochemic al parameters of the binding. A single receptor was found with a K-d O f 1 X 10(-9) M. The number of receptors per cell was 3000-4000 and its molecular weight, as determined by crosslinking experiments, is 87 00 0. The binding of IFN-gamma to its oligodendrocyte receptor is saturab le, specific and temperature-dependent. The receptor-IFN-gamma complex is quickly endocytosed at 37 degrees (the half-time of maximal intern alization is around 1 min). Some cytokines, such as interleukin-1 alph a and interleukin-6, up-regulated the expression of the oligodendrocyt e receptor, but others, such as tumour necrosis factor-alpha, did not. A dramatic increase in receptor expression is induced by lipopolysacc haride but it is not detectable after treatment with concanavalin A.