Waguespack P J, Banks W A, Kastin A J
VA Medical Center, New Orleans, LA 70146.
Brain Res Bull. 1994;34(2):103-9. doi: 10.1016/0361-9230(94)90005-1.
Blood-borne interleukin-2 (IL-2), like other cytokines, is known to affect the central nervous system (CNS). One mechanism by which circulating substances can alter brain function is to directly cross the blood-brain barrier (BBB). We investigated the ability of IL-2 to cross the BBB, the interface between the periphery and the CNS. IL-2 labeled with 125I (I-IL-2) was injected into mice intravenously and its rate of entry into the brain determined by multiple-time regression analysis. I-IL-2 was found to enter the brain about 10 times faster than albumin. Neither morphine nor antibodies to IL-2, IL-1 alpha, or the IL-1 receptor affected the entry of I-IL-2. High performance liquid chromatography (HPLC) confirmed that the radioactivity entering the brain represented intact cytokine. However, excess unlabeled IL-2 was unable to impede the entry of I-IL-2, indicating that this transport is nonsaturable. This contrasts with saturable transport systems found for the cytokines IL-1 alpha and TNF-alpha, but still may explain how IL-2 can exert central effects.
血源性白细胞介素-2（IL-2）与其他细胞因子一样，已知会影响中枢神经系统（CNS）。循环物质改变脑功能的一种机制是直接穿过血脑屏障（BBB）。我们研究了IL-2穿过血脑屏障（即外周与中枢神经系统之间的界面）的能力。将用125I标记的IL-2（I-IL-2）静脉注射到小鼠体内，并通过多次回归分析确定其进入脑内的速率。发现I-IL-2进入脑内的速度比白蛋白快约10倍。吗啡以及针对IL-2、IL-1α或IL-1受体的抗体均不影响I-IL-2的进入。高效液相色谱（HPLC）证实进入脑内的放射性代表完整的细胞因子。然而，过量的未标记IL-2无法阻止I-IL-2的进入，这表明这种转运是非饱和的。这与细胞因子IL-1α和TNF-α的饱和转运系统形成对比，但仍可解释IL-2如何发挥中枢作用。
