Freed B M, Lempert N, Lawrence D A
Department of Surgery, Albany Medical College, NY 12208.
Int J Immunopharmacol. 1989;11(5):459-65. doi: 10.1016/0192-0561(89)90174-4.
The thiol-alkylating agent, N-ethylmaleimide (NEM), was found to inhibit the response of human peripheral blood mononuclear cells to the T-cell mitogen, concanavalin A (Con A). NEM (10 microM) blocked Con A-induced agglutination, production of interleukin-2 (IL-2) and expression of the IL-2 receptors (Tac) without toxicity. In order to determine whether the effects of NEM on lymphokine production were related to inhibition of agglutination, we compared the immunosuppressive effects of NEM with those of cytochalasin A, cytochalasin B and colchicine. NEM did not inhibit E-rosette (ER) formation, suggesting that it does not interfere with actin filaments. Low concentrations of NEM (4 microM) inhibited IL-2 production and Tac expression without inhibiting agglutination, while 6-10 microM NEM blocked agglutination and DNA synthesis as well. In contrast, 5-10 microM cytochalasin B (CB) inhibited ER formation, agglutination, Tac expression and DNA synthesis, but augmented IL-2 production by three- to ten-fold. Colchicine (0.1-10 microM) had no effect on ER formation or agglutination and augmented IL-2 production by as much as 18-fold. However, colchicine blocked Tac expression by greater than 40% and DNA synthesis by greater than 80%. Cytochalasin A (CA), which has the thiol-reactive properties of NEM, the actin filament-disrupting properties of CB, and the microtubule-disrupting properties of colchicine, exhibited the immunosuppressive effects of all three compounds. These studies suggest that the inhibitory effects of NEM on IL-2 production do not appear to be due to reactivity with the cytoskeleton, but are probably due to effects on signal transduction pathways leading to IL-2 production and expression of IL-2 receptors.
巯基烷基化剂N-乙基马来酰亚胺（NEM）被发现可抑制人外周血单个核细胞对T细胞丝裂原刀豆蛋白A（Con A）的反应。NEM（10微摩尔）可阻断Con A诱导的凝集、白细胞介素-2（IL-2）的产生以及IL-2受体（Tac）的表达，且无毒性。为了确定NEM对淋巴因子产生的影响是否与凝集抑制有关，我们比较了NEM与细胞松弛素A、细胞松弛素B和秋水仙碱的免疫抑制作用。NEM不抑制E花环（ER）形成，表明它不干扰肌动蛋白丝。低浓度的NEM（4微摩尔）可抑制IL-2产生和Tac表达，而不抑制凝集，而6 - 10微摩尔的NEM也可阻断凝集和DNA合成。相比之下，5 - 10微摩尔的细胞松弛素B（CB）可抑制ER形成、凝集、Tac表达和DNA合成，但使IL-2产生增加3至10倍。秋水仙碱（0.1 - 10微摩尔）对ER形成或凝集无影响，使IL-2产生增加多达18倍。然而，秋水仙碱可使Tac表达阻断超过40%，DNA合成阻断超过80%。具有NEM的巯基反应特性、CB的肌动蛋白丝破坏特性和秋水仙碱的微管破坏特性的细胞松弛素A（CA）表现出这三种化合物的免疫抑制作用。这些研究表明，NEM对IL-2产生的抑制作用似乎不是由于与细胞骨架的反应性，而是可能由于对导致IL-2产生和IL-2受体表达的信号转导途径的影响。
