组合免疫球蛋白基因片段诱发抗淋巴瘤的体液免疫反应

目的 用含表达不同抗原决定簇的免疫球蛋白重链可变区第1家族（IgHV1）质粒诱发小鼠抗Namalwa淋巴瘤细胞的免疫反应,探索制备通用型核酸疫苗的可能。方法 用RT－PCR分别扩增Namalwa细胞、正常足月新生儿脐带血和成人外周血标本中的IgHV1基因片段,定向克隆到真核表达质粒pcDNA3.0中;将Namalwa细胞的IgHV1质粒（Na-IgHV1）、混合含有Namalwa细胞IgHV1的1－4个抗原决定簇的正常人IgHV1的6种质粒（IgHV1-mix）和空pcDNA3.0质粒分别免疫动物;采用Western印迹和间接免疫荧光法检测3组小鼠抗体产生的情况。结果 IgHV1-mix组和Na-IgHV1组均能诱导出抗Namalwa淋巴瘤细胞特异的免疫反应,诱导产生的抗体能识别存在于Namalwa细胞表面的天然构象的抗原决定簇,两组诱导的抗体均从第4周开始检出,第6周达到高峰,第8周开始下降,抗体滴度无明显差异。结论 组合的IgHV的真核表达质粒有可能作为具有同一IgHV家族基因重排的淋巴瘤的通用型核酸疫苗。

Specific humoral immune response against B-cell lymphoma elicited by mixed immunoglobulin fragments

OBJECTIVE: To explore the feasibility of construction of the universal nucleic acid vaccine against B-cell lymphoma. METHODS: RT-PCR was employed to obtain the immuncy losulin heavy chain variable region (IgHV1) gene fragments of the Namalwa cell, normal fetal umbilical cord blood and adult peripheral blood. Then these RT-PCR products were cloned into the eukaryotic expression vector pcDNA3.0 and sequenced. Six plasmids that had high identities with the germ line genes were mixed to serve as vaccines. Eighteen Balb/c mice were divided randomly into three groups and were immunized respectively with the six mixed plasmids, the specific IgHV1 fragment of the Namalwa cell and the blank plasmid pcDNA3.0. 100 microg plasmid and 5 microg hIL-6 per mouse were injected into the muscle, 3 times in 4 weeks. Western blotting and indirect immunofluorescence staining were used to assess the humoral immune responses against the Namalwa cell. RESULTS: The specific humoral immune responses against the Namalwa lymphoma cell could be induced in both the IgHV1-mix group and the Na-IgHV1 group, and the antibodies could recognize the nature antigenic determinants in the surface of the Namalwa cell. The antibodies could be detected since the fourth week after the first immunization, and reached the climax at the sixth week. There was no significant difference of the titers of the antibodies between the two groups. The antibody couldn't be found in the negative control group. CONCLUSION: The mixed IgHV plasmids can be used as the universal nucleic acid vaccine against the B-cell lymphoma which expresses the same IgHV1 family genes.