Rubio N, de Felipe C
Department of Neuroimmunology, Instituto Cajal, Madrid, Spain.
J Neuroimmunol. 1991 Dec;35(1-3):111-7. doi: 10.1016/0165-5728(91)90166-5.
Interferon gamma (IFN-gamma) is a pleiotropic lymphokine produced by T-lymphocytes which acts as a soluble mediator in immunological reactions. In addition to several immune target cells, such as monocytes and macrophages, it acts on the principal glial population, the astrocytes, inducing Ia antigen expression. We have developed a binding assay for 125I-labeled recombinant murine IFN-gamma, and show that, using this assay, IFN-gamma interacts with a single specific receptor on the murine astrocyte cell membrane. The binding is specific and saturable and it takes place with a Kd = 1.64 x 10(-9) M, with 11,100 receptor molecules per astrocytic cell. The binding shows, as for macrophages, species specificity. Using an immune assay including rabbit antibodies to IFN-gamma and 125I-labeled protein A, we have demonstrated an internalization of the ligand. This is an energy-dependent process, as around 50% of the bound IFN-gamma is endocytosed after 4 h at 37 degrees C when cultures are maintained in complete culture medium.
干扰素γ（IFN-γ）是一种由T淋巴细胞产生的多效性淋巴因子，在免疫反应中作为可溶性介质发挥作用。除了作用于几种免疫靶细胞，如单核细胞和巨噬细胞外，它还作用于主要的神经胶质细胞群——星形胶质细胞，诱导Ia抗原表达。我们开发了一种针对125I标记的重组鼠干扰素γ的结合测定法，并表明使用该测定法，干扰素γ与鼠星形胶质细胞膜上的单一特异性受体相互作用。这种结合是特异性的且可饱和的，其解离常数Kd = 1.64×10^(-9) M，每个星形胶质细胞有11,100个受体分子。与巨噬细胞一样，这种结合具有种属特异性。通过使用包括抗干扰素γ兔抗体和125I标记蛋白A的免疫测定法，我们证明了配体的内化。这是一个能量依赖的过程，当在完全培养基中培养时，在37℃下培养4小时后，约50%结合的干扰素γ被内吞。
