PURINERGIC MODULATION OF T-LYMPHOCYTE ACTIVATION - DIFFERENTIAL SUSCEPTIBILITY OF DISTINCT ACTIVATION STEPS AND CORRELATION WITH INTRACELLULAR 3',5'-CYCLIC ADENOSINE-MONOPHOSPHATE ACCUMULATION
PURINERGIC MODULATION OF T-LYMPHOCYTE ACTIVATION - DIFFERENTIAL SUSCEPTIBILITY OF DISTINCT ACTIVATION STEPS AND CORRELATION WITH INTRACELLULAR 3',5'-CYCLIC ADENOSINE-MONOPHOSPHATE ACCUMULATION
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DOI：
10.1016/0008-8749(86)90199-1
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发表时间：
1986-08-01
影响因子：
4.3
通讯作者：
DECARVALHO, RP
中科院分区：
文献类型：
--
作者：
DOSREIS, GA;NOBREGA, AF;DECARVALHO, RP
探讨了嘌呤能激动剂调节小鼠T淋巴细胞活化和增殖的机制。腺苷和其他化合物如ATP和2-氯腺苷（CIAdo）被发现以剂量依赖的方式阻断刀豆球蛋白A（Con A）诱导的T细胞有丝分裂。不可代谢的腺苷类似物CIAdo是能够抑制T细胞有丝分裂的最有效的药物。细胞外添加的可渗透的cAMP类似物dibutyrl AMP（dbcAMP）也导致了剂量依赖性的T细胞有丝分裂阻滞，虽然与CIAdo相比，效率较低。添加IL-2富集的流体未能逆转由CIAdo或dbcAMP对T细胞有丝分裂的阻断。CIAdo阻断与Con A培养20小时后诱导的T细胞抑制。我们分析了微摩尔浓度的CIAdo对白细胞介素-2（IL-2）产生、IL-2受体（7 D4和3C 7表面抗原）表达以及在体外与Con A培养后诱导IL-2反应性的影响。CIAdo在其抑制T细胞有丝分裂的相同剂量范围内抑制IL-2分泌和诱导IL-2反应性直至对照水平。然而，IL-2受体的细胞表面表达不受影响。短暂孵育静息脾T细胞与CIAdo导致响应细胞中环AMP的剂量依赖性积累。嘌呤能拮抗剂3-异丁基-1-甲基黄嘌呤（IBMX）可显著降低这种作用，但腺苷摄取阻断剂双嘧达莫不能阻止这种作用。CIAdo在其抑制T细胞活化事件的相同剂量范围内引起cAMP积累。细胞外给药dbcAMP刺激的脾T细胞的Con A模仿CIAdo对T细胞活化参数的影响，如通过剂量依赖性阻断IL-2分泌和IL-2反应性诱导所揭示的，而不影响IL-2受体表达。Con A激活的T细胞母细胞与CIAdo的短孵育也导致cAMP的剂量依赖性积累。然后，我们分析了嘌呤和dbcAMP对IL-2介导的活化T细胞生长的影响。嘌呤引起IL-2介导的T细胞增殖的剂量依赖性抑制，并且CIAdo是测试的最有效的嘌呤能激动剂。如果与早期T细胞活化步骤相比，CIAdo对Con A诱导的T母细胞的作用向右偏移。细胞外添加dbcAMP模拟了CIAdo对IL-2依赖性T细胞增殖的作用，其抑制效力明显向右偏移。同时加入IBMX活化的T细胞培养物竞争性拮抗CIAdo对IL-2依赖性增殖的抑制作用。另一方面，IL-2依赖性长期T细胞系CTL-L对CIAdo对IL-2依赖性增殖的抑制作用具有显著抗性，尽管该细胞系仍被dbcAMP阻断。CTL-L细胞中对CIAdo的敏感性丧失与CIAdo引起cAMP积累的能力丧失相关。总之，这些数据表明，嘌呤能激动剂对T细胞活化和增殖参数的选择性作用是通过细胞内cAMP作为第二信使进行的。
The mechanism by which purinergic agonists modulate murine T-lymphocyte activation and proliferation was investigated. Adenosine and other compounds such as ATP and 2-choloradenosine (CIAdo) were found to block T-cell mitogenesis induced by concanavalin A (Con A) in a dose-dependent fashion. The nonmetabolizable adenosine analog CIAdo was the most potent agent capable of inhibiting T-cell mitogenesis. Extracellular addition of the permeable cAMP analog dibutyrl AMP(dbcAMP) also led to a dose-dependent blockade of T-cell mitogenesis, although with less efficiency when compared to CIAdo. Addition of IL-2-enriched fluids failed to reverse blockade of T-cell mitogenesis by CIAdo or dbcAMP. CIAdo blocked T-cell inlargement induced after 20 hr of culture with Con A. We analyzed the effect of micromolar concentrations of CIAdo on interleukin-2 (IL-2) production, expression of IL-2 receptors (7D4 and 3C7 surface antigens), and induction of IL-2 responsiveness after in vitro cultivation with Con A. CIAdo inhibited both IL-2 secretion and induction of IL-2 responsiveness up to control levels in the same dose range it inhibited T-cell mitogenesis. However, cell surface expression of IL-2 receptors was not affected. Short incubations of resting splenic T cells with CIAdo led to a dose-dependent accumulation of cyclic AMP in responding cells. This effect was markedly reduced by the purinergic antagonist 3-isobutyl-l-methylxanthine (IBMX) but was not prevented by the adenosine uptake blocker dipyridamole. CIAdo elicited cAMP accumulation in the same dose range it inhibited T-cell activation events. Extracellular administration of dbcAMP to splenic T cells stimulated by Con A mimicked the effects of CIAdo on T-cell activation parameters, as revealed by a dose-dependent blockade of both IL-2 secretion and IL-2 responsiveness induction, without affecting IL-2 receptor expression. Short incubations of Con A-activated T-cell blasts with CIAdo also led to a dose-dependent accumulation of cAMP. We then analyzed the effect of purines and dbcAMP on IL-2 mediated activated T-cell growth. Purines caused a dose-dependent inhibition of IL-2 mediated T cell proliferation and CIAdo was the most potent purinergic agonist tested. The effect of CIAdo on Con A-induced T blasts was shifted to the right, if compared to earlier T-cell activation steps. Extracellular addition of dbcAMP mimicked the effect of CIAdo on IL-2 dependent T-cell proliferation, with a marked shift to the right in its inhibitory potency. Concomitant addition of IBMX to activated T-cell cultures competitively antagonized the inhibitory effect of CIAdo on IL-2-dependent proliferation. On the other hand, the IL-2-dependent long-term T-cell line CTL-L was markedly resistant to the inhibitory effect of CIAdo on IL-2-dependent proliferation, although this cell line was still blocked by dbcAMP. Loss of sensitivity to CIAdo in CTL-L cells correlated with loss of the ability of CIAdo to elicit cAMP accumulation. Together, these data indicate that the selective effects of purinergic agonists on T-cell activation and proliferation parameters are carried out through intracellular cAMP as a second messenger.