HER-2neu胞外区基因疫苗的免疫避孕作用

Immunocontraception of a gene vaccine based on the extracellular domain of HER-2/neu

目的 :研究HER 2 neu胞外区基因疫苗在免疫避孕中的作用。方法 :构建含人HER 2 neu胞外区的重组质粒pcDNA3 hECD ,以该质粒转染真核细胞C2 C1 2 或注射小鼠股四头肌 ,检测其在体内外表达情况 ;以该质粒基因免疫雌性BALB C小鼠 ,部分小鼠于第 12周以重组蛋白hECDu加强免疫 ,以ELISA方法检测抗HER 2 neu抗体应答 ,3H TdR掺入法检测细胞免疫应答 ,并观察其诱导免疫避孕的情况。结果 :C2 C1 2 转染上清及小鼠股四头肌注射局部均可检测到hECD蛋白的表达。小鼠经基因免疫后可产生较高水平抗体应答 ,抗体水平至少维持 2 8周 ,同时可检测到较高水平细胞免疫应答 (pcDNA3 hECD与对照组SI值分别为 9 5 5和 1 2 5 ) ;基因免疫后小鼠平均产仔数 (3 8± 2 9,对照组为 9 7± 1 6 )明显降低 ,以蛋白加强免疫后产生特异性回忆反应 ,平均产仔数进一步降低 (2 0± 1 7)。而且 ,免疫小鼠产后 4天子宫及卵巢与正常产后鼠相比均无明显区别。结论 :基于HER 2 neu胞外区的基因疫苗免疫小鼠可诱导有效的免疫应答并产生一定免疫避孕效果 ,并且这种避孕作用经特异性蛋白加强免疫可进一步得以提高。

Objective:To study the effects of a gene vaccine based on the extracellular domain of HER-2/neu (hECD) in immunocontraception.Methods:A recombinant plasmid including hECD gene,pcDNA3-hECD,was constructed. The plasmid was transfected into an eukaryotic cell line C 2C 12 ,and injected into the tibilis anterior of mice to analyze the expression of HER-2/neu protein in vitro and in vivo.Female mice were immunized with pcDNA3-hECD,and some mice were boosted with a recombinant protein hECDu at 12-week of DNA immunization. Specific humoral responses to HER-2/neu were analyzed by ELISA,and specific cellular responses were analyzed by 3H-TdR proliferation assay. In addition,contraception effects and histological injuries of uteri were examined.Results:HER-2/neu specific protein could be found in the supernatant of transfected C 2C 12 and the local site of injection. High level of humoral responses was detected in mice immunized with this gene vaccine,with the maintenance of the specific antibodies to the 28-week. High level of cellular responses was also detected (pcDNA3-hECD group: SI=9.55;pcDNA3 group: SI=1.25). The litter size of the pcDNA3-hECD group (Average offspring: 9.7±1.6) was far less than that of the pcDNA3 group (Average offspring: 3.8±2.9). Specific memory immunity was induced by protein boosting,and these mice had a more obvious immunocontraception effect. In comparison with normal mice after delivery,the uteri and ovaries of immunized mice at four-day after delivery had no obvious pathological change.Conclusion:The gene vaccine based on the extracellular domain (ECD) of HER-2/neu could induce immunocontraception in mice.The immunocontraception effect could be enhanced by specific protein boosting.