. 2009, 27(0915): 44-47.
As a third generation vaccine, the nucleic acid vaccine is easy to operate, and of low cost. However, there are some intrinsic risks involved, such as bacterial endotoxin, which should be studied and avoided. Bacterial endotoxin is contained in the outer layer surrounding cell wall of Gram negative bacteria. After being released in vivo, it can cause many pathological changes, such as fever and shock. Some previous in vitro studies show that endotoxin had bad effects on reproductive system of mice. This paper presents experimental studies on the effect of endotoxin on the survival rate and birth rate of immunised mice in vivo. In the experiment, two types of pCR3.1-Sry were extracted by two different methods and used to immunise mice. One method uses the general method, and the other uses a reagent kit. Their difference lies in the fact whether the endotoxin is removed or not. And, their purity and concentration were analyzed and controlled by agarose gel electrophoresis and spectrophotometry. At the same time, sterile ddH2O was injected into mice as control. Then, the immunising and mating tests of mice were carried out. Molecular biological results show that two types of nucleic acid vaccine were at proper concentration and high purity too. The immunity and statistical results show that compared with the group whose endotoxin was removed, the survival rate and the birth rate of the group with endotoxin were severally decreased from 93% to 84% and from 87.5% to 35.7%, respectively. At the same time, data for endotoxin-removed group is close to the control group. All the results indicate that endotoxin interfused in the nucleic acid vaccine has adverse effect on immunised mice, especially, on the reproductive system.
