Diamantstein T, Osawa H
Mol Immunol. 1984 Dec;21(12):1229-36. doi: 10.1016/0161-5890(84)90015-4.
There is increasing evidence suggesting that the monoclonal antibodies ART-18, AMT-13 and anti-Tac recognize species-specific antigenic determinants of the interleukin-2 (IL-2) receptors of rat, mouse and human origin, respectively. In order to compare directly the molecules (glycoproteins) recognized by these antibodies, concanavalin A (ConA) activated T-lymphocytes of the respective species were surface labeled with 125I, after which the materials immunoprecipitated by the appropriate anti-IL-2 receptor antibodies were subjected to SDS-PAGE analysis. The noncross-reacting antibodies ART-18 and AMT-13 both precipitated a 50-55-kD molecule. The anti-Tac-reactive material (the putative human IL-2 receptor) is considerably different (60-65 kD) from those precipitated by antibodies ART-18 and AMT-13 (the putative rat and mouse IL-2 receptors). An indirect binding assay using the anti-mouse IL-2 receptor antibody AMT-13 showed that, after addition of ConA to spleen cell cultures, T-lymphocytes expressed IL-2 receptors before the onset of the ConA-induced DNA synthesis. The ConA-induced expression of the IL-2 receptor is apparently a transient event. IL-2 receptor bearing cells progressively lost their receptors (within 6 days) when recultured in the absence of ConA. Cells re-exposed to ConA regained IL-2 receptors. Short exposure of T-cells (thymocytes) to ConA or the nonmitogenic compound phorbol myristate acetate (PMA) is not sufficient to trigger IL-2 receptor expression. Murine thymocytes incubated with PMA for 30 min or with ConA for 4 hr (mitogen-pulsed T-cells) failed to bind the anti-IL-2 receptor antibody AMT-13 and to absorb IL-2 activity present in semipurified IL-2 preparations, but they proliferated vigorously in response to the same IL-2 preparations. The IL-2 preparations, when absorbed with thymocytes, lost: (1) the capacity to generate IL-2 receptors, and (2) the capacity to induce proliferation of mitogen-pulsed cells; but they retained the capacity to induce proliferation of T-lymphoblasts. These results suggest the existence of a factor, IL-2 receptor inducing factor (RIF), present in the IL-2 preparations. It is postulated that RIF is a prerequisite for the acquisition of IL-2 receptors and consequently for IL-2 responsiveness by lectin-activated cells.
越来越多的证据表明，单克隆抗体ART-18、AMT-13和抗Tac分别识别大鼠、小鼠和人源白细胞介素-2（IL-2）受体的物种特异性抗原决定簇。为了直接比较这些抗体识别的分子（糖蛋白），用伴刀豆球蛋白A（ConA）激活相应物种的T淋巴细胞，并用125I进行表面标记，然后将用适当的抗IL-2受体抗体免疫沉淀的物质进行SDS-PAGE分析。非交叉反应抗体ART-18和AMT-13均沉淀出一个50 - 55kD的分子。抗Tac反应性物质（假定的人IL-2受体）与ART-18和AMT-13抗体沉淀的物质（假定的大鼠和小鼠IL-2受体）有很大不同（60 - 65kD）。使用抗小鼠IL-2受体抗体AMT-13的间接结合试验表明，在向脾细胞培养物中添加ConA后，T淋巴细胞在ConA诱导的DNA合成开始之前就表达了IL-2受体。ConA诱导的IL-2受体表达显然是一个短暂事件。当在没有ConA的情况下重新培养时，携带IL-2受体的细胞会逐渐失去其受体（在6天内）。重新暴露于ConA的细胞会重新获得IL-2受体。T细胞（胸腺细胞）短时间暴露于ConA或非促有丝分裂化合物佛波酯肉豆蔻酸酯（PMA）不足以触发IL-2受体表达。用PMA孵育30分钟或用ConA孵育4小时的小鼠胸腺细胞（有丝分裂原刺激的T细胞）不能结合抗IL-2受体抗体AMT-13，也不能吸收半纯化IL-2制剂中存在的IL-2活性，但它们对相同的IL-2制剂有强烈的增殖反应。当用胸腺细胞吸收IL-2制剂时，其失去了：（1）产生IL-2受体的能力，以及（2）诱导有丝分裂原刺激细胞增殖的能力；但它们保留了诱导T淋巴母细胞增殖的能力。这些结果表明在IL-2制剂中存在一种因子，即IL-2受体诱导因子（RIF）。据推测，RIF是凝集素激活细胞获得IL-2受体并因此对IL-2产生反应的先决条件。
