目的观察日本血吸虫(Schistosoma japonicum)感染小鼠肝脏、脾脏的病变情况及经吡喹酮治疗后小鼠外周血及脾脏中滤泡辅助性T细胞(Tfh)及其表面分子的变化。方法将15只6~8周龄C57BL/6雌性小鼠随机分为吡喹酮治疗感染组(治疗组)、未治疗感染组(未治疗组)和未感染组,每组5只。治疗组和未治疗组每只小鼠经腹部皮肤感染日本血吸虫尾蚴20条;治疗组小鼠于感染后6周给予200 mg/(kg·d)吡喹酮灌胃治疗,连续3 d;未感染组和未治疗组不治疗。于治疗后4周解剖各组小鼠,观察小鼠肝脏和脾脏病变情况,计算减虫率和肝脏减卵率。采用流式细胞术检测各组小鼠外周血和脾脏Tfh占CD4~+T细胞的比例,检测其表面分子可诱导T细胞共刺激分子(ICOS)和程序性死亡受体1(PD-1)的表达情况。采用ELISA检测小鼠血清中可溶性虫卵抗原(SEA)特异性IgG抗体水平。结果与未治疗组比较,治疗组小鼠的肝脏和脾脏病变明显较轻,减虫率和肝脏减卵率分别为84.1%和69.1%(P<0.01)。治疗组、未治疗组和未感染组外周血和脾脏Tfh细胞的比例分别是14.7%~18.0%和15.6%~25.0%、13.7%~16.7%和12.4%~18.2%、2.5%~6.8%和4.9%~8.0%,治疗组和未治疗组明显高于未感染组(P<0.01),治疗组和未治疗组差异无统计学意义(P>0.05)。治疗组、未治疗组和未感染组外周血和脾脏中ICOS的表达水平分别为0.7%~1.1%和1.8%~6.8%、1.3%~3.2%和4.1%~7.0%、0.2%~0.3%和0.5%~0.8%,未治疗组高于治疗组和未感染组(P<0.01);治疗组脾脏ICOS的表达水平明显高于未感染组(P<0.01),而外周血的表达水平与未感染组差异无统计学意义(P>0.05)。治疗组、未治疗组和未感染组外周血和脾脏中Tfh细胞PD-1水平分别为0.5%~1.5%和4.5%~8.9%、0.8%~1.9%和4.1%~10.7%、0.4%~0.8%和1.2%~1.8%,未治疗组明显高于未感染组(P<0.01),治疗组与未治疗组差异无统计学意义(P>0.05)。吡喹酮治疗后4周,治疗组、未治疗组和未感染组的SEA特异性IgG水平(A450值)分别为2.015±0.061、1.969±0.038和0.139±0.128,治疗组与未治疗组差异无统计学意义(P>0.05)。结论吡喹酮治疗后,日本血吸虫感染小鼠肝脏、脾脏组织病变明显减轻,外周血和脾脏Tfh细胞ICOS的表达比未治疗组显著降低。 Objective To observe the pathological changes of liver and spleen in mice infected with Schistosoma japonicum and the changes of follicular helper T cells (Tfh) and its surface molecules in mouse peripheral blood and spleen after praziquantel treatment. Methods Fifteen C57BL / 6 female mice aged 6-8 weeks were randomly divided into praziquantel treatment group (untreated group), untreated group (untreated group) and non-infected group (n = 5). Each mouse in the treatment group and untreated group was infected with 20 cercariae of Schistosoma japonicum through the skin of the abdomen. The mice in the treatment group were treated with praziquantel 200 mg / (kg · d) for 6 weeks after infection for 3 consecutive days; Infection and untreated groups were not treated. Four weeks after treatment, the mice in each group were dissected and the pathological changes in the liver and spleen were observed. The worm reduction rate and the rate of liver reduction were calculated. Flow cytometry was used to detect the ratio of Tfh to CD4 ~ + T cells in peripheral blood and spleen of mice in each group. ICOS and PD-1 were detected on the surface of mice by flow cytometry. The expression of the situation. ELISA was used to detect the level of soluble IgG antigen in serum of mice. Results Compared with the untreated group, the liver and spleen of the mice in the treatment group were significantly lighter and the rates of worm reduction and liver reduction were 84.1% and 69.1%, respectively (P <0.01). The proportion of Tfh cells in the peripheral blood and spleen in the untreated group and untreated group were 14.7% -18.0% and 15.6% -25.0%, 13.7% -16.7% and 12.4% -18.2%, 2.5% -6.8% and 4.9% -8.0%, the treatment group and the untreated group were significantly higher than the non-infected group (P <0.01), there was no significant difference between the treatment group and the untreated group (P> 0.05). The expression of ICOS in peripheral blood and spleen of the untreated group and non-infected group were 0.7% -1.1% and 1.8% -6.8%, 1.3% -3.2% and 4.1% -7.0%, 0.2% -0.3% And 0.5% ~ 0.8%, respectively. The levels of ICOS in the untreated group were higher than those in the untreated group and the untreated group (P <0.01). The expression of ICOS in the spleen of the untreated group was significantly higher than that in the uninfected group (P <0.01) There was no significant difference in uninfected group (P> 0.05). The levels of PD-1 in peripheral blood and spleen of Tfh cells in treatment group, untreated group and non-infected group were 0.5% -1.5% and 4.5% -8.9%, 0.8% -1.9% and 4.1% -10.7%, 0.4% 0.8% and 1.2% ~ 1.8%, respectively, in the untreated group was significantly higher than that in the non-infected group (P <0.01). There was no significant difference between the untreated group and the untreated group (P> 0.05). Four weeks after praziquantel treatment, SEA-specific IgG levels (A450 values) in the untreated and untreated groups were 2.015 ± 0.061, 1.969 ± 0.038 and 0.139 ± 0.128, respectively, with no difference between the untreated and untreated groups Statistical significance (P> 0.05). Conclusion After the treatment with praziquantel, the pathological changes of liver and spleen in mice infected with Schistosoma japonicum were significantly alleviated. The expression of ICOS in peripheral blood and spleen Tfh cells was significantly lower than that in untreated mice.