T-CELL PROLIFERATION INVOLVING THE CD28 PATHWAY IS ASSOCIATED WITH CYCLOSPORINE-RESISTANT INTERLEUKIN-2 GENE-EXPRESSION
T-CELL PROLIFERATION INVOLVING THE CD28 PATHWAY IS ASSOCIATED WITH CYCLOSPORINE-RESISTANT INTERLEUKIN-2 GENE-EXPRESSION
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DOI：
10.1128/mcb.7.12.4472
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发表时间：
1987-12-01
影响因子：
5.3
通讯作者：
THOMPSON, CB
中科院分区：
文献类型：
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作者：
JUNE, CH;LEDBETTER, JA;THOMPSON, CB
CD 28是一种在人T细胞的主要亚群的表面上表达的同源二聚体糖蛋白，其最近被鉴定为免疫球蛋白超基因家族的成员。单克隆抗体与纯化的T细胞上的CD 28抗原的结合不会导致增殖;然而，先前的研究表明，CD 28刺激和蛋白激酶C激活的佛波醇肉豆蔻酸酯乙酸酯（PMA）的组合导致T细胞增殖，其独立于辅助细胞和T细胞受体-CD 3复合物的激活。在本研究中，抗CD 28刺激对细胞周期进程和白细胞介素2（IL-2）和IL-2受体系统的影响进行了研究纯化的外周血CD 28 + T细胞的原代培养。单独用CD 28刺激静息（G 0）细胞后，对细胞大小或DNA合成没有可测量的影响。PMA单独激活T细胞3小时后，细胞体积出现轻微（8%）增加，但未进行DNA合成。相比之下，CD 28与PMA组合的T细胞刺激导致apx中细胞体积的进行性增加。刺激后12至14 h，100%的细胞。北方印迹（RNA印迹）分析显示，单独的CD 28刺激不能引起IL-2受体α链或IL-2 mRNA的表达，并且与先前的研究雅阁，单独的PMA刺激导致IL-2受体转录物的积累，但没有检测到IL-2 mRNA。与此相反，T细胞刺激的CD 28和PMA的组合导致IL-2转录本的出现和IL-2受体mRNA的表达增强。功能研究表明，由CD 28和PMA刺激诱导的增殖对环孢霉素完全耐受，与由CD 3-T细胞受体复合物诱导的T细胞活化相反。环孢素被发现不影响积累的IL-2 mRNA的CD 28加PMA刺激后，虽然有没有检测到的IL-2 mRNA的刺激后，由CD 3在药物的存在。此外，刺激CD 28结合固定化的CD 3抗体引起的IL-2 mRNA的表达，这是一个显着的增强，在一定程度上，抵抗环孢霉素的影响。这些研究表明，CD 28分子与蛋白激酶C活化协同作用，诱导IL-2基因表达，并证明即使在环孢菌素存在下，CD 28途径的刺激也能引起剧烈的T细胞增殖，并且环孢菌素不阻止16-2 mRNA的转录，如先前所建议的。此外，这些研究结果表明，在体内的CD 28分子的潜在作用可能是增加刺激后的CD 3-T细胞受体分子复合物的IL-2的生产，从而扩大抗原特异性免疫应答。最后，这些结果提供了进一步的证据，表明CD 28分子以不同于CD 3-T细胞受体诱导的增殖的生物化学方式触发T细胞增殖。
CD28 is a homodimeric glycoprotein expressed on the surface of a major subset of human T cells that has recently been identified as a member of the immunoglobulin supergene family. The binding of monoclonal antibodies to the CD28 antigen on purified T cells does not result in proliferation; however, previous studies have shown that the combination of CD28 stimulation and protein kinase C activation by phorbol myristate acetate (PMA) results in T-cell proliferation that is independent of both accessory cells and activation of the T-cell receptor-CD3 complex. In the present study, effects of stimulation by anti-CD28 on cell cycle progression and on the interleukin 2 (IL-2) and IL-2 receptor system have been investigated on primary cultures of purified peripheral-blood CD28+ T cells. There was no measurable effect on cell size or on DNA synthesis after stimulation of resting (G0) cells by CD28 alone. After 3 h of activation of T cells by PMA alone, a slight (8%) increase in cell volume occurred that did not progress to DNA synthesis. In contrast, T-cell stimulation by CD28 in combination with PMA resulted in a progressive increase in cell volume in .apprx. 100% of cells at 12 to 14 h after stimulation. Northern blot (RNA blot) analysis revealed that CD28 stimulation alone failed to cause expression of the alpha chain of the IL-2 receptor of of IL-2 mRNA, and in accord with previous studies, stimulation by PMA alone resulted in the accumulation of IL-2 receptor transcripts but no detectable IL-2 mRNA. In contrast, T-cell stimulation by the combination of CD28 and PMA resulted in the appearance of IL-2 transcripts and enhanced expression of IL-2 receptor mRNA. Functional studies revealed that the proliferation induced by CD28 and PMA stimulation was entirely resistant to cyclosporine, in contrast to T-cell activation induced by the CD3-T-cell receptor complex. Cyclosporine was found not to affect the accumulation of IL-2 mRNA after CD28 plus PMA stimulation, although there was no detectable IL-2 mRNA after stimulation by CD3 in the presence of the drug. Furthermore, stimulation by CD28 in combination with immobilized CD3 antibodies caused a striking enhancement of IL-2 mRNA expression that was, in part, resistant to the effects of cyclosporine. These studies indicate that the CD28 molecule synergizes with protein kinase C activation to induce IL-2 gene expression and demonstrate that stimulation by the CD28 pathway can cause vigorous T-cell proliferation even in the presence of cyclosporine and that cyclosporine does not prevent transcription of 16-2 mRNA, as has been suggested previously. Moreover, these findings suggest that a potential role for the CD28 molecule in vivo may be to augment IL-2 production after stimulation of the CD3-T-Cell receptor molecular complex and thereby to amplify an antigen-specific immune response. Finally, these results provide further evidence that the CD28 molecule triggers T-cell proliferation in a manner that differs biochemically fro CD3-T-cell receptor-induced proliferation.