Ishikawa Fumio, Nakano Hideki, Seo Akira, Okada Yayoi, Torihata Hideko, Tanaka Yuriko, Uchida Tetsuya, Miyake Hidekazu, Kakiuchi Terutaka
Department of Immunology, Toho University School of Medicine, Tokyo, Japan.
Immunology. 2002 Jul;106(3):354-62. doi: 10.1046/j.1365-2567.2002.01434.x.
Previously, we reported that 100 Gy X-ray irradiation followed by 24 hr incubation up-regulates CD80 expression in murine B lymphoma cells, A20-2J. In the present study, we analysed the underlying mechanisms of such up-regulation using A20-HL cells derived from A20-2J cells. Irradiation of A20-HL cells with 100 Gy enhanced CD80 expression. Incubation of untreated A20-HL cells with those 100 Gy irradiated induced up-regulation of CD80 expression. Irradiation of A20-HL cells also up-regulated the expression of tumour necrosis factor-alpha (TNF-alpha) and CD40 ligand (CD40L), and the amount of immunoprecipitable TNF-alpha and CD40L in cell lysates. The addition of anti-TNF-alpha or anti-CD40L monoclonal antibody (mAb) to the incubation of irradiated A20-HL cells partially inhibited up-regulation of CD80 expression, and the addition of both antibodies together almost completely inhibited the up-regulation, suggesting that irradiation up-regulated the CD80 expression through the induction of TNF-alpha and CD40L expression. Irradiation also increased the accumulation of CD80, TNF-alpha and CD40L mRNA. n-tosyl-l-phenylalanine chloromethyl ketone (TPCK), a nuclear factor (NF)-kappaB inhibitor, markedly decreased irradiation-induced accumulation of CD80 mRNA and CD80 expression. FK506, a calcineurin inhibitor, and nifedipine, a calcium channel inhibitor, inhibited not only the expression of TNF-alpha and CD40L, but also the up-regulation of CD80 on irradiated A20-HL cells. These results strongly suggested that irradiation induced TNF-alpha and CD40L expression, which then up-regulated CD80 mRNA and CD80 expression through activation of NF-kappaB transcription factor in A20-HL cells.
此前，我们报道过，100 Gy的X射线照射后再孵育24小时会上调小鼠B淋巴瘤细胞A20 - 2J中的CD80表达。在本研究中，我们使用源自A20 - 2J细胞的A20 - HL细胞分析了这种上调的潜在机制。用100 Gy照射A20 - HL细胞可增强CD80表达。将未处理的A20 - HL细胞与经100 Gy照射的细胞共同孵育可诱导CD80表达上调。照射A20 - HL细胞还上调了肿瘤坏死因子-α（TNF-α）和CD40配体（CD40L）的表达，以及细胞裂解物中可免疫沉淀的TNF-α和CD40L的量。在照射后的A20 - HL细胞孵育体系中添加抗TNF-α或抗CD40L单克隆抗体（mAb）可部分抑制CD80表达的上调，同时添加两种抗体几乎可完全抑制上调，这表明照射通过诱导TNF-α和CD40L表达来上调CD80表达。照射还增加了CD80、TNF-α和CD40L mRNA的积累。核因子（NF）-κB抑制剂N-对甲苯磺酰-L-苯丙氨酸氯甲基酮（TPCK）显著降低了照射诱导的CD80 mRNA积累和CD80表达。钙调神经磷酸酶抑制剂FK506和钙通道抑制剂硝苯地平不仅抑制了TNF-α和CD40L的表达，还抑制了照射后A20 - HL细胞中CD80的上调。这些结果有力地表明，照射诱导了TNF-α和CD40L表达，进而通过激活A20 - HL细胞中的NF-κB转录因子上调了CD80 mRNA和CD80表达。
