基因工程变链菌防龋疫苗的研制

Preparation of Recombinant Vaccine Against Dental Caries of Streptococcus Mutans

本文采用我们自己构建的基因工程龋齿疫苗菌株，大罐发酵培养３批、菌体收量平均湿重为２．６７ｇ／Ｌ，表达率为４４．２７％。菌体经超声裂解，硫酸铵和链霉素粗提，再经吸附层检，凝胶过滤和离子交换柱层析等步骤纯化精提ＧＴＦ抗原３批。提纯的ＧＴＦ抗原，平均比活，提纯倍数和收率，分别为５８．３４ｕ／ｍｇ、６．０８倍和１９．２５％。此抗原经ＳＤＳ－ＰＡＧＥ电泳，分子量为５５ＫＤ，纯度达到９６．７％，并对湿度具有较好的稳定性能。

In this study,the recombinant dental caries vaccine strain constituted by the authors was cultured in mobile pilot plant fermentor containing 30 liters of LB media.The yield of the microorganism (mean wet weight) was 2.67g/L,the expression level reached 44.27%.Havested bacterial cells were disrupted by ultrasonication.Glucosyltransferase (GTF) antigen was purified by crude extraction with ammonium suphate and streptomycin,followed by hydroxylapatite,Sephacryl S200HR,DEAESepharose F.F. column chromatographies.The specific activity,purification fold and recovery of purifies GTF antigen were 58.34U/mg,6.08 fold and 19.25% respectively.Its molecular mass was 55KD.The purity reached 96.7% on SDSPAGE.This antigen possessed very good stability to temperature and it also showed better immunogenicity when rabbits were immunized with dental caries vaccine made from this antigen.