转基因番茄可食防龋疫苗免疫大鼠的实验研究?

目的用表达变异链球菌表面蛋白PAcP和霍乱毒素B亚单位融合蛋白的转基因番茄免疫SD大鼠，检测其免疫原性，探索研制安全、有效的可食用防龋疫苗的可能性。方法选择雌性 SD 大鼠18只，建立龋齿模型，随机分成3组(n=6)，分别为转基因番茄组(实验组)、变异链球菌灭活全菌免疫组(阳性对照组)、非转基因番茄组(阴性对照组)，免疫方式为灌胃免疫，每周免疫1次，连续免疫4周。分别于首次免疫前1 d 和每次免疫1周后采集血液、唾液样品，用酶联免疫吸附实验法检测血清中免疫球蛋白 G(IgG)、唾液中分泌型免疫球蛋白 A(SIgA)抗体水平；鼠龄70 d 时处死动物，并取上下颌骨进行龋齿计分。结果免疫后，实验组和阳性对照组大鼠血清中 IgG、唾液中 SIgA 抗体水平与阴性对照组比较差异有统计学意义(P <0.05)；实验组和阴性对照组在 Dx 级外的各级差异有统计学意义(P <0.05)。结论转基因番茄防龋疫苗具有免疫原性，能够诱导实验动物产生有效的免疫应答，降低龋齿的发生。

The study of oral immunization with the transgenic tomato anti-caries vaccine in SD rats

Objective SD rats were immuned with the transgenic tomatoes which carried fused gene of a region of PAc Strep-tococcus mutants and cholera toxin B subunit.The immunogenicity was tested to explore secure and economic edible vaccines a-gainst dental caries.Methods A total of 18 eighteen-day-old female SD rats were subdivided randomly into three groups:the exper-imental group which were fed with transgenic tomato juice containing chimaera protein PAcP/CTB;the positive control group which were treated with deactivated S.mutans;the negative control group which were not treated with transgenic tomato juice.Rats were immuned once per week for four weeks.Blood and saliva were collected at one day before the first immunity and one week after each immunization.IgG of blood serum and SIgA of saliva were detected using the enzyme-linked immunosorbent assay (indirect ELISA) testing.On day 70,rats were terminated.The maxillary and mandibular bones were subsequently taken out to count dental caries′scores.Results Post immunization,the experimental group and the positive control group had statistical significant levels of speci-ficity IgG in serum and SIgA in saliva compared to the negative control group (P <0.05).There was a significance difference be-tween the experimental group and the negative control group except in Dx levels of caries loss (P <0.05).Conclusion The targeted protein expressed on the transgenic tomatoes is immunogenic,which can effectively induce mucous membrane immune response and the systematical immunoreaction to suppress the occurrence of the dental caries.