CD40激发对恶性B淋巴细胞体外生物学行为的影响

目的 观察重组人可溶性CD40配体（rhsCD40L)及CD40L基因转染细胞（CD40L-TC）对恶性B淋巴细胞体外生物学行为的影响，探讨rhsCD40L在肿瘤生物治疗中的可能作用。方法 利用基因工程技术获得了rhsCD40L和CD40L-TC，分别与恶性B淋巴细胞株XG2，XG7，U266，8226，Raji及Daudi共同作用，分析了CD40激发对肿瘤细胞的体外增殖（锥虫蓝计数法），细胞周期（碘化丙锭掺入法），细胞表面共刺激分子的表达（免疫荧光标记法）以及细胞凋亡（Anexin-V-ETTC法）的效应。结果 （1）恶性B淋巴细胞株CD40表达呈异质性，XG2高表达CD40，8266，Raji和Daudi中度表达，而XG7和U266不表达CD40。显微镜下观察发现，rhsCD40L(5μg/ml）可引起XG2或Daudi细胞的同型聚集，该效应在作用6-8h后即可出现；与CD40L-TC细胞共育后（肿瘤细胞；CD40L-TC=5：1），XG2，Raji和Daudi细胞可粘附于CD40L-TC表面；（2）rhsCD40L和CD40L-TC均可显著抑制XG2，Raji和Daudi细胞的体外增殖，导致XG2细胞呈现G1期阻滞，而Raji和Daudi细胞阻滞于G2期，并诱导XG2，Raji,Daudi细胞的凋亡，凋亡率分别为：XG2细胞23.3%和18.8%,Raji细胞阻滞于G2期，并诱导XG2，Raji,Daudi细胞的凋亡，凋亡率分别为：XG2细胞23.3%和18.8%,Raji细胞11.6%和8.9%,Daudi14.2%和15.9%;(3)表型分析显示；rhsCD40L/CD40L-TC可明显上调XG2,Raji和Daudi细胞CD95的表达水平以及Raji细胞CD80的表达，而下调Raji细胞CD18的表达。结论 rhsCD40L能直接并显著地抑制恶性B淋巴瘤细胞株Raji,Daudi和多发性骨髓瘤细胞株XG2的体外增殖，诱导其凋亡，并上调Raji细胞免疫共刺激株Raji,Daudi和多发性骨髓瘤细胞株XG2的体外增殖，诱导其凋亡，并上调Raji细胞免疫共刺激分子CD80的表达，具有膜型CD40L的同样生物学功能，故rhsCD40L具有潜在的抗恶性B淋巴细胞肿瘤的作用。

Effect of CD40 on the in vitro biological behavior of malignant B lymphocytes

OBJECTIVE: To explore the effect of recombinant human soluble CD(40) ligand (rhsCD(40)L) and CD(40)L cDNA transfected cell (CD(40)L-TC) on the behavior of malignant B lymphocytes, and investigate the possibility of using rhsCD(40)L as a new bio-factor in tumor immunotherapy. METHOD: rhsCD(40)L and CD(40)L-TC were obtained by gene recombinant techniques. Multiple myeloma cell lines, XG2, XG7, U266 and 8226, B-lymphoma cell lines, Raji and Daudi were selected to detect responses to rhsCD(40)L and CD(40)L-TC stimulation. Cell growth curve, cell cycle, early apoptosis as well as membrane surface molecules on these cell lines were analyzed. RESULTS: (1) The expression levels of CD(40) molecule on malignant B lymphocytes showed heterogeneity. High level of CD(40) on XG2, moderate on 8266, Raji, and Daudi, and no expression on U266 and XG7 were detected. The rhsCD(40)L stimulation gave rise to a typical homo-type cell aggregation of XG2 and Daudi. Meanwhile, at least 10 to 20 of CD(40)(+) XG2 or CD(40)(+) Daudi cells were found adherent to one pre-treat ed CD(40)L-TC. (2) Co-incubation with rhsCD(40)L (5 micro g/ml), or CD(40)L-TC (tumor cell: CD(40) = 5:1) resulted in a significant inhibition of in vitro cell growth of XG2, Raji and Daudi, with G(1)-phase arrest for XG2 and G(2)-phase for Raji and Daudi. These two kinds of CD(40) stimulators induced XG2, Raji and Daudi cells to apoptosis in vitro. The apoptotic rate for XG2 was 23.3% (rhsCD(40)L) and 18.8% (CD(40)L-TC), for Daudi 14.2% and 15.9%, and for Raji 11.6% and 8.9% respectively. (3) Phenotype analysis showed that CD(95) expression levels were significantly up-regulated on XG2, Raji and Daudi after stimulation with rhsCD(40)L or CD(40)L-TC, and CD(80) and CD(18) expression levels on Raji were respectively enhanced and decreased. CONCLUSION: The abilities to directly inhibit XG2, Daudi and Raji cell proliferation, to induce themapoptosis, as well as to up-regulate immune co-stimulator molecule CD(80) expression on Raji cells would make rhsCD(40)L a potential bio-factor for tumor immuno-therapy.