猪圆环病毒2型对外周血单核细胞中PD-1,PD-L1和IL-21转录水平的影响

Effects of PCV2 on Transcription Levels of PD-1,PD-L1 and IL-21 in PBMCs

用猪圆环病毒2型(PCV2)体外感染外周血单核细胞,建立荧光定量PCR方法检测PCV2的病毒载量;同时,在PCV2感染后12 h、24 h、36 h、48 h、60 h、72h收集细胞,抽提RNA进行反转录,检测PD-1、PD-L1和IL-21的转录水平变化,分析评价PCV2感染对PD-1、PD-L1和IL-21的转录水平变化的影响。结果显示,PD-1在感染外周血单核细胞后72 h显著升高,达到峰值;PD-L1在感染后转录水平都显著升高,48 h达到峰值;IL-21在感染后48 h转录水平最低。结果表明,PCV2不仅能够在体外感染外周血单核细胞,而且随着病毒载量的增加,导致PD-1、PD-L1和IL-21的转录水平显著升高。以上结果表明,PCV2感染导致PD-1、PD-L1和IL-21的转录水平升高,通过激活PD-1/PD-L1通路,从而抑制IL-21的转录水平;相反,IL-21刺激PD-1、PD-L1的转录水平升高。研究结果为探索PCV2的致病机制和控制PCV2的感染提供了理论基础。

Porcine circovirus type 2(PCV2) was used to infect peripheral blood mononuclear cells in vitro.Fluorescent quantitative PCR was established to detect the viral load of PCV2,which was used to analyze and evaluate the effect of PCV2 infection on the transcription level changes of PD-1,PD-L1 and IL-21.After inoculation with PCV2,the cells were collected at 12,24,36,48,60 and 72 hours respectively and RNA was extracted for reverse transcription to detect expression levels of PD-1,PD-L1 and IL-21.The results further showed that PCV2 can not only infect peripheral blood mononuclear cells in vitro,but also the transcription levels of PD-1,PD-L1 and IL-21 significantly increase with the increase of viral load.Among them, PD-1 increased significantly and reached a peak at 72 h after PCV2 infection.PD-L1 transcription levels increased significantly at 12-72 hours and reached a peak at 48 h after PCV2 infection.IL-21 transcription levels were the lowest at 48 hours after PCV2 infection.These results indicated that PCV2 infection leads to the increase in the transcription levels of PD-L1 and IL-21,which activates the PD-1/PD-L1 pathway, and thereby inhibiting the transcription level of IL-21.On the contrary, IL-21 stimulates PD-1 and PD-L1 and the transcription levels are elevated, leading to immune suppression in the body.This study provides a new theoretical basis for the pathogenic mechanism of PCV2 to control PCV2 infection.