不同凋亡水平T细胞来源的ALD-DNA对抗双链DNA抗体产生的影响

Effect of ALD-DNA derived from cells with different apoptotic levels on the induction of anti-double-stranded DNA antibody

研究不同凋亡水平T细胞来源的ALD-DNA(activated lymphocyte-derived DNA)对抗双链DNA抗体产生的影响。用尼龙毛柱法分离小鼠脾脏T细胞,分别提取不同凋亡水平T细胞的DNA定义为未凋亡ALD-DNA、低凋亡水平ALD-DNA、中凋亡水平ALD-DNA和高凋亡水平ALD-DNA,并免疫同系BALB/c小鼠;用ELISA方法检测血清中IgG类抗双链DNA抗体的水平及其亚型;用考马斯亮蓝法检测免疫小鼠尿蛋白的含量。结果显示,ALD-DNA的凋亡水平与其诱导产生的抗双链DNA抗体水平成正相关,二者的相关系数r=0.852;不同凋亡水平的ALD-DNA诱导的抗双链DNA抗体均以IgG1为主,但IgG2a和IgG2b的水平在高凋亡ALD-DNA免疫组有明显增高;低凋亡ALD-DNA、中凋亡ALD-DNA和高凋亡ALD-DNA免疫小鼠均有显著蛋白尿形成,并且高凋亡ALD-DNA免疫组的尿蛋白含量有明显增高。该结果表明,高凋亡水平的ALD-DNA免疫同系小鼠更易诱导高水平的致病性IgG类抗双链DNA抗体产生,凋亡DNA可能在系统性红斑狼疮(SLE)发生发展过程中发挥了重要作用,这为我们能更加深入的理解SLE的发生机制提供了有力的实验依据。

In order to investigate the role of different apoptotic levels of activated lymphocyte-derived DNA （ALD-DNA） in the induction of anti-dsDNA antibodies in syngeneic mice, splenic T cells were enriched by passage over the nylon wool and stimulated with ConA. Normal BALB/c mice were immunized with syngeneic non-apoptotic ALD-DNA, low apoptotic ALD-DNA, median apoptotic ALD-DNA and high apoptotic ALD-DNA subcutaneously on the dorsal skin. The anti-dsDNA antibody response and the isotypic analysis of the anti-dsDNA antibodies were determined by ELISA. The urine protein was measured with the coomassie brilliant blue assay. Compared with the non-apoptotic ALD-DNA, it was demonstrated that all the low apoptotic ALD-DNA, median apoptotic ALD-DNA and high apoptotic ALD-DNA could induce the production of anti-dsDNA antibody responses. Furthermore, with the increase of apoptotic levels of ALD-DNA, the level of anti-dsDNA antibodies was also elevated. Isotypic analysis revealed that the anti-dsDNA antibodies were IgG1 predominantly. However, the IgG2a and IgG2b anti-dsDNA antibodies were significantly increased in the high apoptotic ALD-DNA immunized mice. In addition, compared with the normal mice, all the low apoptotic ALD-DNA, median apoptotic ALD-DNA and high apoptotic ALD-DNA immunized mice showed dramatically higher urine proteins. As noted, the urine protein was significantly higher in the high apoptotic ALD-DNA treated mice. In contrast, the non-apoptotic ALD-DNA failed to induce the proteinuria in syngenic BALB/c mice. These results suggest that the high apoptotic ALD-DNA was more easily to induce high levels of pathological anti-dsDNA antibodies in syngeneic mice, which indicates that apoptotic DNA was the driven of anti-dsDNA antibodies in ALD-DNA. These data may facilitate deeper understanding of the pathogenesis of SLE.