变形链球菌表面蛋白和葡糖基转移酶基因疫苗免疫防龋实验研究:唾液和血清抗体水平测定

An Experimental Study on PAc and GTF Gene Vaccines of Streptococcus Mutans against Rats Caries: Antibody Levels in Saliva and Serum

目的 将基因疫苗pcDNA3_pac和pcDNA3_gtfB经腺周注射免疫定菌大鼠 ,观察唾液和血清抗体的变化 ,证实基因疫苗的免疫原性。方法 36只Wistar大鼠分为 6个免疫组 :pcDNA3_pac ,pcDNA3_gtfB ,pcDNA3_pac联合pcDNA3_gtfB ,阳性对照灭活变形链球菌 ,阴性对照pcDNA3及PBS液组。建立龋攻击定菌鼠模型 3个月 ,各组大鼠均以 10 0 μg剂量免疫定菌鼠 3次 ,ELISA法检测唾液SIgA和血清IgG水平。 结果 疫苗组在首次免疫后第 33天(第 5周 )都出现较高水平的唾液SIgA ,在第 75天 (第 11周 )后达最高水平 ,并持续至实验结束。成组单因素方差分析唾液SIgA水平在总体上各实验组间存在差异 (P <0 0 1或P <0 0 5 ) ,q检验分析在联合免疫组和全菌细胞组最高 ,单基因疫苗免疫组次之 ,pcDNA3与PBS组最低 ;血清IgG水平在 4个免疫组之间没有差异 (P >0 0 5 ) ,但都高于空白及阴性对照组 (P <0 0 5 )。结论 pcDNA3_pac和pcDNA3_gtfB腺周途径免疫定菌Wistar大鼠 ,能有效诱导唾液SIgA和血清IgG抗体产生 。

Objective\ The purpose of this study is to examine the levels of salivary SIgA and serum IgG induced by pcDNA3_pac and pcDNA3_gtfB immunization, so as to testify the antigenity of the two gene vaccines.Methods\ 36 28_day_old Wistar rats were divided into 6 groups, among which 3 experimental groups were vaccinated with pcDNA3_pac, pcDNA3_gtfB or pcDNA3_pac combined with pcDNA3_gtfB, respectively, one positive control was vaccinated with inactive whole cell of S.mutans JBP and other two negative controls were injected with the vector pcDNA3 or PBS buffer, respectively. All vaccines and materials were delivered with 100 μg by submandibular gland injection for 3 times. Then the restricted bacterial model of rat was constructed. Following that all rats were fed with cariogenic diet Keyes 2000\+# for 3 months, saliva and serum samples were collected to assay SIgA or IgG levels by ELASA.Results\ The salivary S_IgA levels both in pcDNA3_pac combined with pcDNA3_gtfB group and inactive S.mutans cell group were higher than others (P<0 01). In groups of pcDNA3 and PBS buffer, they were lowest (P<0 01). The serum IgG levels in the three experimental groups and positive control were higher than that in negative control (P<0 05). It was important that salivary SIgA in groups of gene vaccine and inactive S.mutans vaccination reached its peak at the 11th week after the first inoculation and kept until the end of the study. Conclusion\ Both pcDNA3_pac and pcDNA3_gtfB can express immunogenic protein and induce immune responses of mucosal and humoral immune system in gnobobiotic rats. It is also indicated that the joint gene vaccines immunization is an optimal choice for anticaries strategy.