中文摘要：

目的分析田鼠巴贝虫可溶性抗原蛋白组分，寻找敏感、特异的诊断候选抗原。方法用田鼠巴贝虫感染BALB／c小鼠。待红细胞感染率达到高峰时（感染率〉70％），收集虫体，制备可溶性抗原；同时收集BALB／c小鼠的本底血清和感染田鼠巴贝虫7、14、21、28、35、42、49和56d后的血清；聚丙烯酰胺凝胶电泳法（SDS．PAGE）分析可溶性抗原的蛋白组分，蛋白质免疫印迹法（Westernblot）分析可溶性抗原的免疫反应性，选择阳性反应条带进行质谱鉴定和序列分析。结果可溶性抗原经SDS—PAGE分析，可观察到9条主带和12条次带，蛋白条带的相对分子质量（Mr）介于（12～185）×10^3（kDa）；Westernblot结果显示感染后7d的混合鼠血清可识别Mr为40和45kDa的蛋白条带且反应较强，感染后14d的混合鼠血清可识别Mr为40、45、54和95kDa的蛋白条带．感染后21d的混合鼠血清可识别腑为27、40、45、54、95和110kDa的蛋白条带，感染后28d至感染56d的混合鼠血清均可识别Mr为27、40、45、54、95和110kDa的蛋白条带且随着感染时间的延长出现其他的弱反应条带。阳性反应条带通过质谱鉴定和序列分析，共确定336个蛋白，包括表面抗原、热休克蛋白70、血清反应抗原、含t-复合物多肽伴侣蛋白的Eta亚基1和未命名蛋白。结论田鼠巴贝虫可溶性抗原中Mr为40、45、54kDa的组分是较好的诊断候选抗原，在田鼠巴贝虫病诊断中的应用前景值得进一步研究。

英文摘要：

Objective To analyze the fractional proteins and immunoreactivity of the soluble antigens from Babesia microti （B. microti）, and find the candidate antigens for diagnosis with high sensitivity and specificity. Methods BALB/c mice were inoculated with B. microti-infected red blood cells by intraperitoneal injection. The B. microti were collected from the infected red blood ceils when the infection rate reached its peak （infection rate 〉 70%）, then the soluble antigens were extracted by repeated freezing-thawing and ultrasonic method. The mice sera before and after the infection with B. microti for 7, 14, 21, 28, 35, 42, 49 and 56 days were also collected. The polyacrylamide gel electrophoresis （SDS-PAGE） was used to analyze protein components of the soluble antigens of B. microti and the Western blot was used to analyze the immunoreactivity of the soluble antigens with the pooled mice sera before and after the infection. The specific positive protein bands were identified by Liquid chromatography electrospray ionisation tandem mass spectrometry （LC-ESI-MS/MS）, and the amino acid sequences of the proteins were analyzed by bioinformatics tools. Results The results from SDS-PAGE analysis indicated that the soluble antigens of B. microti showed distinct protein bands with the range between 12 and 185 ×10^3 （kDa, relative molecular mass, Mr）, among which 9 main bands and 12 minor bands were obtained. In the Western blot analysis, the protein bands with Mr at 40 and 45 kDa could be recognized by pooled mice sera 7 days after infection; the protein bands with Mr at 40, 45, 54 and 95 kDa could be recognized by pooled mice sera 14 days after infection;the protein bands with Mr at 27, 40, 45, 54, 95 and 110 kDa could be recognized by pooled mice sera 21 days after infection. While, the protein bands with Mr at 27, 40, 45, 54, 95, 110 kDa and other weak-reactive bands were recognized by pooled mice sera 28 - 56 days after infection, and the reaction became stronger with the infection continued. There w