PCV2与PPV体外混合感染猪肺泡巨噬细胞对细胞因子的影响

Cytokine mRNA expression of porcine pulmonary alveolar macrophage in vitro in response to porcine circovirus type 2 and porcine parvovirus co-infection

通过PCV2与PPV混合感染猪肺泡巨噬细胞,探讨PCV2与PPV体外混合感染的致病机制。体外分离猪肺泡巨噬细胞(PAMs),分为PCV2、PPV、PCV2/PPV混合感染组和对照组,采用实时荧光定量PCR技术检测PAMs中PCV2与PPV病毒拷贝数及细胞因子IFN-γ、TNF-α和IL-10的mRNA转录水平的变化。结果表明,PPV能在PAMs中增殖,而PCV2在肺泡巨噬细胞中增殖效率较低;PCV2能促进PPV增殖;PPV单独感染PAMs后能促进IFN-γ和TNF-α的表达;PCV2单独感染PAMs后能促进IFN-γ的表达,并在感染早期促进TNF-α的表达;PCV2与PPV混合感染后能显著抑制IFN-γ的表达,在感染早期对TNF-α的促进作用高于PCV2单独感染组,并能短暂的刺激IL-10的过量表达。说明PCV2与PPV混合感染存在协同致病作用,两种病毒共同刺激了TNF-α和IL-10的大量表达,抑制了IFN-γ的表达。

This study was to define the pathogenesis of coinfection of porcine cirvovirus type 2（PCV2） and porcine parvovirus（ PPV ） in vitro. Porcine alveolar macrophages （ PAMs） were isolated, and divided into PCV2 infection group, PPV infection group, PCV2/PPV coinfection group and control group. PCV2 and PPV nucleic acid, and mR-NA levels of cytokines IFN-γ, TNF-α and IL-10 in PAMs were detected by realtime-PCR. The results showed that PPV could proliferate in PAMs, but the proliferation effi-ciency for PCV2 was low. PCV2 infection increased the expressions of IFN-γ mRNA and TNF-α mRNA expres-sion, PCV2/PPV coinfection lowered the expression level of IFN-γ mRNA. However, the level of TNF-α in PCV2/PPV coinfection group was higher than that in PCV2 group during early infection,and a transient IL-10 increasing was detected as well. These results suggested that the suppression of IFN-γand over-expression of TNF-αand IL-10 caused by PCV2/PPV coinfection might contribute to the inhibition of cellular immunity.