弓形虫复合疫苗滴鼻免疫小鼠诱导肠淋巴细胞变化

Dynamics of intestinal lymphocyte in mice treated with complex vaccine against Toxoplasma gondii by intranasal immunization

目的观察弓形虫可溶性速殖子抗原(STAg)联合蜂胶和γ干扰素(IFN-γ)滴鼻免疫BALB/c小鼠后诱导肠上皮内淋巴细胞及其亚群的动态变化。方法将96只5～6周龄雌性BALB/c小鼠随机分为免疫组和对照组,免疫组以弓形虫复合疫苗(20μg STAg+40μg蜂胶+1 000 U IFN-γ)滴鼻免疫,对照组以磷酸盐缓冲液滴鼻;分别于滴鼻2次(间隔2周)后第1、2、3、4、6、8、10和12周处死小鼠,分离肠上皮内淋巴细胞(IEL),计数并涂片;免疫细胞化学法检测CD4+、CD8+T细胞亚群水平。结果免疫组小鼠IEL的T淋巴细胞增生第2周达高峰(2.27×105),之后逐渐降低;在第1、2、3和4周对照组T淋巴细胞数分别为(0.81×105)、(0.74×105)、(0.87×105)、(0.74×105)个,免疫组IEL中T淋巴细胞数分别为(1.79×105)、(2.27×105)、(2.07×105)、(1.69×105)个,2组差异均有统计学意义(F=8.42,P<0.01);IEL中以CD8+T淋巴细胞增生为主,对照组CD8+T细胞水平无明显变化,免疫组CD8+T细胞明显增生,第2周达峰值(50.5%),随后逐渐下降,第1、2、3、4和第6周分别为43.60%、50.51%、44.70%、40.45%、39.73%,与对照组的25.71%、26.37%、29.31%、27.54%、26.35%比较,差异均有统计学意义(F=6.38,P<0.05);第1、2周免疫组CD4+/CD8+比值低于对照组,差异有统计学意义(F=5.74,P<0.05)。结论 STAg联合蜂胶和IFN-γ滴鼻免疫BALB/c小鼠,可诱导肠上皮内淋巴细胞持续性免疫应答。

Objective To observe the dynamics of intestinal intraepitheliai lymphocyte subsets in mice intranasaly immunized with soluble tachyzoites antigen（STAg） in association with propolis and gamma interferon（ IFN-γ ）. Methods Ninety-six female BALB/c mice were randomly divided into immunized and control group and immunized with 2 doses of STAg plus propolis and IFN-~ against Toxoplasma gondii and phosphate buffer, respectively, at an interval of 2 weeks. The mice were killed 1,2,3,4,6,8,10 ,and 12 weeks after the 2nd dose,respectively, and intestinal intraepithelial lymphocytes （[EL） were isolated and counted. Percentage of CD4＋ and CD8＋ T cells was determined by immunocytochemistry. Results The number of [EL of the mice in immunized group reached a peak value at week 2（2. 27 × 105） and was significantly higher than that of in the control group during weeks 1-4 （F = 8.42 ,P 〈 0. 01 ）. The numbers of CD4＋and CD8＋ T cells were both higher than those of the control. CD8＋ T cells was significantly higher at weeks 1,2,3,4 ,and 6 than those in the control group （ F = 6. 38, P 〈 0. 05 ）, while CD4＋ T cells in immunized group increased significantly at week 2 and 3 （ F = 5.64, P 〈 0. 05 ）. The ratio of CD4＋/CD8＋ T ceils was higher at week 1 and 2 （ F = 5. 74, P 〈 0. 05 ）. Conclusion The immunization with STAg in association with propolis and IFN-γ by intranasal drip can effectively induce immune responses of IEL.