猪圆环病毒2型感染后猪外周血淋巴细胞IL-2、IL-4、IL-10、IL-12p40、IFN-γ和TNF-α mRNA转录的变化

The Effects of PCV2 Experimental Infection on Transcriptional Levels of IL-2,IL-4,IL-10,IL-12p40,IFN-γ and TNF-α mRNA of Peripheral Blood Lymphocytes

采用竞争定量RT-PCR技术(qcRT-PCR)对PCV2感染组和健康对照组外周血淋巴细胞中IL-2、IL-4、IL-10、IL-12p40、IFN-γ和TNF-α的mRNA转录水平进行分析。结果表明,在14和21 DPI(Days post inoculation)感染组Th1类细胞因子IL-2 mRNA转录水平分别为对照组的5.1(P<0.01)和24.0(P<0.01)倍;IL-12p40 mRNA转录水平在14和21 DPI分别为对照组的1.7(P<0.05)和1.2(P<0.05)倍;感染组IFN-γmRNA转录水平除在7 DPI低于对照组外(P<0.05),在28和42 DPI均明显高于对照组,分别为对照组的38.2(P<0.01)和4.0(P<0.05)倍。Th2类细胞因子波动较为明显,28 DPI IL-4 mRNA转录水平显著高于对照组(P<0.01);感染组IL-10mRNA在7(P<0.01)和14 DPI(P<0.05)的转录水平均显著高于对照组,而在35 DPI明显低于对照组(P<0.05)。在整个试验过程中TNF-αmRNA转录水平没有发生明显变化。上述6种细胞因子mRNA变化结果显示,PCV2感染猪Th1细胞的细胞因子表达水平升高,而Th2细胞的细胞因子在28 DPI前后出现明显波动,尤其是在35 DPI IL-10 mRNA显著下降(P<0.05),提示PCV2感染可造成猪体内Th1/Th2免疫应答的失衡,导致细胞免疫应答功能增强而体液免疫应答下降。

The transcriptional levels of IL-2, IL-4, IL-10, IL-12p40, IFN-γ and TNF-α of peripheral blood lymphocytes derived from piglets experimentally inoculated with PCV2 at 40 days old were detected by quantitative competitive RT-PCR （qcRT-PCR）. The results showed that IL-2 and IL-12p40 mRNA levels were notably increased in the affected pigs at 14 （P〈0.01, P〈0.05） and 21 days post-inoculation （DPI） （P〈0.01, P〈0.05）, respectively. IFN-γ mRNA levels were notably decreased at 7 DPI （P〈0.05） ,then upregulated statistically at 28 （P〈0.01） and 42 DPI （P〈0.05）. IL-4 mRNA levels of the inoculated pigs were statistically higher than the control pigs at 28 DPI （P〈0.01）. Whereas IL-10 mRNA levels were significantly increased at 7 （P 〈0.01） and 14 DPI （P〈0.05）, then clear decrease were detected at 35 DPI （P〈0.05）. TNF-α mRNA expressions appeared not obviously be affected by PCV2 infection. In conclusion, the results indicated that PCV2 infection could cause imbalance of Th1/Th2 driven immune response, resulting in the impairment of humoral immunity along with the enhancement of cellular immunity.