新生期小鼠卡介苗接种对脾脏T细胞功能亚群发育的影响

Effects of Bacillus Calmette-Guerin vaccination on immune functional development of splenic T cell in neonatal mice

目的 研究接种卡介苗对新生小鼠T细胞功能发育的影响。方法 新生清洁级BALB/c小鼠卡介苗接种与未接种组各 8只, 4周后取脾细胞进行CD4、CD25、CD44等表面标志及CD3+细胞胞内IFN γ、IL 10和IL 4等细胞因子的双标流式检测,并RT PCR方法检测脾细胞转录因子T bet、Foxp3、GATA 3mRNA的表达。结果 卡介苗接种组小鼠脾脏CD4+T细胞百分率为(23 .50±2. 59)%明显低于对照组(47. 38±10. 41)% (P<0. 01),但CD4+T细胞中CD25+和CD44+百分率[ (24. 92±2. 74)%和(89. 29±2. 56)% ]高于对照组 [ (20. 27±2. 85)%和 (82. 98±5. 51)% ](P<0 05);卡介苗接种组CD3+细胞中IFN γ、IL 10阳性细胞百分率分别为 ( 6. 52±2. 40 )%、(14 81±3. 65)%,高于对照组[ (3 .13±2. 03)%、(10. 90±1. 61)% ] (P<0. 05),IL 4表达两组差异无统计学意义[ (1. 17±0 46) % 和 (1. 51±0. 75)%,P>0. 05]。T betmRNA表达卡介苗接种组较未接种组明显增强[T bet/β actin为 0 44±0. 11和 0. 28±0. 06,P<0. 05 ],但Foxp3、GATA 3mRNA表达两组差异无统计学意义[Foxp3 /β actin为 0. 27±0 .11和 0. 30±0. 16,GATA 3 /β actin为 0 .46±0. 08和 0. 50±0 .10,P均>0. 05]。结论 卡介苗接种能诱导新生小鼠体内产生Th1反应。

Objective Almost every neonate receives Bacillus Calmette-Guerin (BCG) vac cination in China. The authors′ previous study showed that BCG promoted cord b lood monocyte-derived dendritic cells maturation and induced high level of inte rleukin (IL)-10, medium level of interferon (IFN)-γ, but low level of IL-4 p roduction by cord naive T cells. The experiments in the present study were desi gned to explore the effects of neonatal BCG vaccination on immune functional dev elopment of splenic T cells in mice in vivo.Methods Neonatal BALB/c mice were inoculated with BCG intraperiotoneally. Fo ur weeks later, spleen cells of mice were isolated and surface molecular markers of CD4, CD25 and CD44 and intracellular IFN-γ, IL-10, and IL-4 in CD3+ T cells were detected by flow cytometry. Furthermore, mRNA expression of transcri ption factor T-bet, Foxp3 and GATA-3 were analyzed by RT-PCR. Results The percentage of total CD4+ T cells decreased [(23.50±2.59)% vs. (47.38±10.41)%, P<0.01] but the percentage of CD25+ [(24.9 2±2.74)% vs. (20.27±2.85)%, P<0.05] and CD44+ [(89.29±2.56 )% vs. (82.98±5.51)%, P<0.05] T cells in CD4+ T cells was higher in BCG-vaccinated mice than that in controls. Meanwhile, the percentage of IF N-γ positive [(6.52±2.40)% vs. (3.13±2.03)%, P<0.05] and IL -10 positive [(14.81±3.65)% vs. (10.90±1.61)%, P<0.05] but no t IL-4 positive [(1.17±0.46)% vs (1.51±0.75)%, P>0.05] cells in CD3+T cells of BCG-vaccinated mice was significantly higher than that of n on-BCG-vaccinated mice. In comparison with BCG-naive mice, T-bet was signif icantly high in BCG-vaccinated mice [T-bet/β-actin 0.44±0.11 vs. 0 .28±0.06, P<0.05], but there was no significant difference in GATA-3 [GATA-3/β-actin 0.46±0.08 vs. 0.50±0.10,P>0.05] and Foxp3 [Foxp3/β-actin vs. 0.27±0.11 and 0.30±0.16, P>0.05] mRNA ex pression between the two groups. Conclusion Neonatal BCG vaccination could induce strong Th1 but weak Th2 respons e as reported previously. Though neonatal BCG vaccination was not capable of in ducing CD4+CD25+ regulatory T cell response with Foxp3 expression, it caused increase of IL-10+ CD3+ cells which might represent some regulatory T cell s producing IL-10.