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目的用组织病理学方法观察几种SARS DNA疫苗对BALB/c小鼠重要器官的影响,为研制安全有效的SARS DNA疫苗奠定基础. 方法用RT-PCR的方法从SARS冠状病毒(SARS-CoV)基因组中扩增出M片段、E片段、N片段和S基因的两个主要片段S1, S2,然后将这些基因片段分别亚克隆至pVAC真核表达载体,制备出几种SARS DNA疫苗pVAC-S1、 pVAC-S2、 pVAC-M、 pVAC-E、pVAC-N.用这些疫苗分别或联合免疫BALB/c小鼠后,取小鼠重要器官心、肝、脾、肺、肾,观察其组织病理学改变. 结果鼠心、脾和肾未见明显的组织病理学异常,但部分小鼠的肝和肺表现出下列病理变化:肝:出现片状肝细胞染色加深和肝细胞核固缩等凋亡早期改变,部分还可见到肝细胞水变性和肝窦变窄甚至消失等病变.肺:肺泡隔增厚,肺泡轮廓消失,或肺组织淤血水肿,甚至出现支气管肺炎改变.同时,在pVAC空质粒对照组也可见个别小鼠出现上述肝、肺病变. 结论由于对肝、肺产生组织病理学异常改变,制备高效、安全的SARS DNA疫苗还有待进一步研究和完善,载体的选择和质粒的用量也是必须加以考虑的问题.“,”Objective To observe the effect of several SARS DNA vaccines on vital organs of BALB/c mice by a histopathological method, so as to lay foundation for developing an effective and safe DNA vaccine against SARS. Methods The genes encoding M, E, N and S1, S2 (two main DNA fragments of S gene) were amplified from SARS-CoV genome RNA by RT-PCR method. Then several DNA vaccines, pVAC-S1, pVAC-S2, pVAC-M, pVAC-E, pVAC-N, were obtained by subcloning these DNA fragments into pVAC eukaryotic expression vector, respectively. After the BALB/c mice were immunized with these vaccines alone or in combination, the organs including heart, liver, spleen, lung and kidney were taken from the mice for histopathology study. Results No obvious changes were observed in heart, spleen and kidney, but part of the mice presented histopathological damage in liver and lung. In liver, the changes at an early stage of apoptosis or necrosis process, such as the cytoplasm deeper stained and the nuclei becoming denser in hepatocytes were found in some immunized mice. Hydropic degeneration and hepatic sinusoids becoming narrow or even disappeared were also observed in part of the hepatic tissue sections. In lung, thickening of alveolar septum and disintegration of alveolar structure, or lung edema and congestion, and even the pathological change of bronchial pneumonia were observed. However, pathological changes in liver and lung mentioned above could also be observed in a few mice treated with pVAC empty plasmid as a vector control. Conclusion On account of the toxicity in liver and lung, further investigation and advancement as well as appropriate vector and dosage should be concerned to develop effective and safe DNA vaccines against SARS.