肺炎链球菌自溶酶（LytA）黏膜免疫小鼠的生物安全性评价

目的开展肺炎链球菌自溶酶（LvtA）生物安全性的动物实验研究，为其申报生物制品鉴定提供实验数据。方法制备纯化的重组表达LytA蛋白，以6．5μg、13．0μg和19．5μg3种剂量黏膜免疫BALB／c小鼠，根据《中华人民共和国国家标准食品安全性毒理学评价程序》（GB15193．1—1994）进行LytA的90d喂养试验、传统致畸试验及遗传毒性试验检测，以分析其生物安全性。结果90d喂养试验结果显示各实验组小鼠与对照组小鼠的体重增长趋势一致，且各时间点检测的小鼠体重均无显著性差异（P〉0．05）。传统致畸试验检测发现各实验组小鼠与对照组小鼠心脏、肺、肝脏、肾、脾、胃、子宫重量、红细胞和白细胞数目、谷丙转氨酶、尿素氮、总胆固醇、甘油三脂、血糖、总蛋白、自蛋白及球蛋白等指标均元明显差异（P〉0．05）。小鼠骨髓嗜多染红细胞微核试验结果显示LytA经鼻腔黏膜免疫小鼠无遗传毒性。结论利用90d喂养试验、传统致畸试验及遗传毒性试验证明LytA鼻腔黏膜免疫BALB／c小鼠安全、毒副作用不明显，有良好的生物安全性，值得进一步研究。

Biosafety Assessment of Mucosal Immunization of Mice with LytA from Streptococcus pneumoniae

Objective To evaluate thc biosafety of mucosal immunization of BALB/c mice with LytA from Streptococcus pneumoniae. Method After mucosal delivery of LytA 3 times with 3 concentrations （6.5 μg, 13.0μg and 19.5μg）, 90 days feeding test, teratogenicity test and genetic toxicity test were conducted to assess biosafety of LytA. Results There was no significant difference on weight of heart, lung, liver, kidney, spleen, stomach, uterus and body,and levels of major biochemical parameters between experimental groups and negative group （P〉0.05）. Furthermore,in micronucleus test,no significant difference on the rate of the micronucleus was found between experimental groups and negative group （P〉0.05）. Conclusion Mucosal immunization of mice with LytA was safe and no mutation and tertogenicity were observed.