重组猪胸膜肺炎放线杆菌毒素ApxI对小鼠的急性毒性和免疫保护性研究

Acute Toxicity and Immunoprotection of Recombinant ApxI Toxin of Actinobacillus pleuropneumoniae in Mice

研究了猪胸膜肺炎放线杆菌毒素Ⅰ重组表达蛋白(包括粗提包涵体和经复性处理的重组蛋白)对小鼠的急性毒性以及免疫保护性,并和天然毒素Ⅰ(由APP血清10型菌的培养物上清提取)做了对比。在急性毒性试验中,3种蛋白均以200μg只的剂量腹腔注射小鼠,并分别于24h、7d和14d后眼眶放血致死,检测血常规和血液生化相关指标。结果表明,3种蛋白均不引起小鼠死亡,且重组表达蛋白对小鼠的生长、血常规和血液生化指标没有显著影响。在免疫保护性试验中,用3种蛋白乳化后免疫小鼠,2周后加强免疫1次,并在每次免疫后采血检测其效价,二免2周后用致死剂量的APP血清10型菌(1.09×108cfu)腹腔攻毒。结果表明,天然毒素和复性的重组表达蛋白均具有良好的免疫原性,对小鼠具有较好的免疫保护效力。

Acute toxicity and immunoprotection of Actinobacillus pleuropneumoniae （APP） ApxI toxin recombinant proteins （include crude inclusion bodies and refolded recombinant protein） were evaluated in mice, and compared with the natural ApxI extracted from culture supernatant of APP serotype 10. In the acute toxicity experiment, the three proteins were intraperitoneally injected into Kunming mice in a dose of 200μg per mouse. The body and organ weight, heamatological and biochemical indexes were examined at 24h, 7 days and 14 days post administration. There was no death after the intraperitoneal administration of the three proteins, and no significant change was found in the body weight, organ indexes, heamatological and biochemical indexes. To study their immunoprotection, the three proteins were emulsified with Freund＇ s adjuvant respectively and vaccinated the mice twice with a 2-week of interval. Two weeks after the second vaccination, the mice were challenged intraperitoneally with a lethal dose of APP serotype 10 （1.09 x 10^8cfu）, and serums were examined by an ApxI-specific ELISA. The results revealed that the recombinant protein had a good immunogenicity and could induce protection immune reaction.