【作者】 戚春建；

【导师】 张学光；

【作者基本信息】 苏州大学 ， 免疫学， 2003， 硕士

【摘要】 CD40分子激发可诱导B细胞产生多种生物学效应：Ig的分泌和同型转换、细胞表面分子的上调性表达如：CD23、B7、CD54和CD95等分子及诱导细胞因子的分泌如IL-2、IL-6、IL-8、TNFa和GM-CSF等。而恶性B淋巴细胞表达的CD40分子激发后可产生不同的生物学效应：涉及到肿瘤细胞生长抑制、细胞凋亡或促进细胞增殖等。一种分子为何能介导如此复杂而多样的生物效应?这引起人们的广泛关注，但迄今为止确切的原因尚未明了。因此，探讨CD40激发后信号传导及其涉及分子为阐明上述科学问题提供实验依据。鉴此CD40分子信号传导及其涉及的分子是当今免疫学领域的一个研究热点。近期发现的能与CD40胞浆结构域结合的蛋白分子TRAFs、JAK3、ERK等分别或共同参与了不同类型细胞和不同状态下CD40分子的信号传导，其中TRAFs家族成员在CD40信号传导中的作用倍受关注。 本论文以表达CD40分子的人多发性骨髓细胞为研究对象，着重探讨了CD40分子信号对肿瘤细胞生物学行为的影响及其分子机制，我们的实验结果显示：(1)三种CD40激发方式均可显著抑制人MM细胞株XG2的体外增殖，导致XG2细胞呈现G1期阻滞，并诱导XG2细胞凋亡；(2)XG2细胞激发后TRAF1、TRAF2、TRAF5、TRAF6明显下调，而人MM细胞株XG7细胞激发后TRAF1、TRAF5、TRAF6都明显上调；(3)低剂量的CD40激发型抗体能通过诱导IL-6自分泌使XG2细胞增殖；高剂量的CD40抗体激发，虽然也诱导IL-6的分泌，但是同时也可上调膜型TNF(mTNF)和TNFRI的表达，并以后者的效应占主导作用，从而引起细胞凋亡。在我们近期的对两例MM新鲜标本的进行的相关实验中都不同程度的证实了以上在细胞株中的结果。上述结果首次证实了：CD40信号在MM细胞上生物学功能的多样性可能与不同类型TRAF谱和CD40信号对多发性骨髓瘤细胞生物学行为的影响及其分子机制提要不同强度的CD4O分子激发有关。更多还原

【Abstract】 The stimulation of CD40 can induce many biological effects on B cells. CD40 signaling is essential for thymus-dependent induction of immunoglobulin isotype synthesis itself as well as for the switching of the isotype of the heavy chain,. Ligation of CD40 mediates a broad variety of immune and inflammatory responses, such as the expression of adhesion molecules (CD23, B7, CD54, CD95 et al), cytokines (IL-2, IL-6, IL-8, TNFa, GM-CSF et al), matrix-degrading enzymes and apoptotic mediators. CD40 on the malignant B lymphocytes can trigger cell proliferation, growth arrested or apoptosis, but the exact biological behavior is unclear. However, recent studies suggested that in B lymphocytes TRAFs, JAK3 and ERKs are essential for CD40 signaling. Among them, TRAFs are the most importantadaptor protein.Our result show: (1) Co-incubation with the three stimulators induced a significant inhibition of cell growth of XG2 with Gl-phase arrest in vitro. Interestingly, we also found that the two kinds (cross-linking and ligation) of CD40 stimulators induced XG2 cells to apoptosis in vitro. The apoptotic rate for XG2 was 23.3%(CD40mAb), 18.9%(CD40L-TC) and 24.5%(rhsCD40L) respectively; (2) TRAF1, TRAF2, TRAF5, TRAF6 was downregulated after XG2 was triggered by CD40, while TRAF 1,5,6 was upregulated in XG7; (3) low concentrations of 5C11 induced proliferation of XG2, while high concentrations of 5C11 resulted in homotypic aggregation of XG2, strongly suppressed its proliferation and led to apoptosis after 24 hours of treatment. This effect is attributed to upregulate expression of the membrane-associated TNF(mTNF) and TNFR1. All these results have been conformed by our researching in primary myeloma cells. Conclusion: The behavior diversity of CD40 signal on MM cells may be related to the type and intensity of CD40更多还原