日本血吸虫感染小鼠肝脏及脾脏NKT细胞的变化

目的观察日本血吸虫感染后小鼠肝脏及脾脏自然杀伤(NK)T细胞的动态变化特征。方法将24只6～8周龄雌性BALB/c小鼠随机分为4组,其中3组每鼠经腹部皮肤感染(14±2)条日本血吸虫尾蚴,分别于感染后3、6、12周剖杀小鼠,分离肝脏及脾脏单个核淋巴细胞,应用异硫氰酸荧光素(FITC)标记的CD49b单克隆抗体及藻红蛋白(PE)标记的CD3e单克隆抗体标记细胞,流式细胞仪检测CD3/CD49b双阳性的NKT细胞占单核淋巴细胞的比例。体外刺激实验中将分离的正常小鼠脾脏单个核淋巴细胞,分别用SEA、虫卵蛋白、虫卵脂质作为刺激物,观察其中NKT细胞的比例变化。结果日本血吸虫感染小鼠脾脏中NKT细胞,于感染后12周比例为(4.73±0.41)%,显著高于对照组比例(2.07±0.12)%(P0.01);肝脏NKT细胞在感染后3周(8.03±0.23)%与对照组(8.60±1.48)%无明显变化,但感染后6周及12周NKT比例明显上升,分别为(15.90±0.76)%和(21.00±0.30)%,与对照组相比差异有统计学意义(P0.01)。体外实验结果显示,刺激物为SEA和虫卵脂质时,NKT细胞的比例分别为(0.77±0.03)%及(0.80±0.06)%,明显高于空白对照组(0.53±0.03)%及虫卵蛋白组(0.50±0.06)%(P0.05)。结论日本血吸虫感染导致小鼠脾脏及肝脏中NKT细胞比例上调,其上调可能与虫卵可溶性抗原中的脂质组分有关。

Changes of NKT cells in livers and spleens of mice infected with Schistosoma japonicum

Objective To understand the changes of NKT cells in the livers and spleens of mice infected with Schistosoma japonicum.Methods Twenty-four female BALB/c mice aged 6-8 weeks were randomly divided into 4 groups.Three groups of mice were infected with（14±2）cercariae of S.japonicum.In 3,6 and 12 weeks post-infection,the mice were randomly chosen from each group and sacrificed resectively and the lymphocytes were harvested from the livers and spleens.The cells were stained with fluorescein-isothiocyanate（FITC）-conjugated anti-mouse pan-NK cells（CD49b）and phycoerythrin（PE）anti-mouse CD3e monoclonal antibodies,respectively.The proportion of NKT cells was analyzed by flow cytometry.In the experiment in vitro,the lymphocytes from spleens of normal mice were harvested and stimulated with SEA,the protein constituents of eggs and lipid constituents of eggs,respectively.The proportion of NKT cells was also analyzed by flow cytometry.Results The proprotion of splenic NKT cells in lymphocytes in 12 weeks post-infection was（4.73±0.41）%,which was significantly higher than that of the control（2.07±0.12）%（P0.01）;the proportions of hepatic NKT cells in lymphocytes in 6 weeks（15.90±0.76）% and 12 weeks（21.00±0.30）% post-infection were also significantly higher than those of the control（8.60%±1.48%）（P0.01）.In addition,the proportions of NKT cells in lymphocytes were（0.77±0.03）% and（0.80±0.06）%,respectively,when the cells were stimulated with SEA or the lipids of eggs in vitro,which were higher than those of the groups of control（0.53 ±0.03）% and protein constituents（0.50±0.06）%（P0.05）.Conclusion The proportion of splenic and hepatic NKT cells in monolymphocytes is up-regulated following S.japonicum infection,which is mainly due to the stimulation of lipids in the eggs.