Bovine viral diarrhea virus (BVDV) has been detected in peripheral blood mononuclear cells (PBMCs) of immunocompetent animals, not being clear whether the development of a specific humoral immune response can prevent BVDV infection. The aim of this study was to evaluate the ability of non-cytopathic BVDV to replicate and produce infectious virus in PBMCs from calves pre-infected with BVDV and to elucidate the immunomodulatory effect of BVDV on these cells in an in vitro model. Quantification of virus was by quantitative PCR, while its replicative capacity and shedding into the extracellular environment was evaluated by viral titration. Apoptosis was assessed by flow cytometry analysis of annexin V and propidium iodide, and by expression of caspase-3/7. Flow cytometry was used to analyze the expression of CD14/CD11b/CD80, CD4/CD8/CD25, MHC-I/MHC-II and B-B2 markers. Our results showed that PBMCs from cattle naturally infected with BVDV were more susceptible to in vitro BVDV infection and showed a more severe apoptosis response than those from naïve animals. Non-cytopathic BVDV in vitro infection also resulted in a lack of effect in the expression of antigen presentation surface markers. All these findings could be related to the immunosuppressive capacity of BVDV and the susceptibility of cattle to this infection.

中文翻译：

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BVDV的允许性和共感染分子在预先感染BVDV的犊牛的PBMC上缺乏表达。

在具有免疫能力的动物的外周血单核细胞（PBMC）中已检测到牛病毒性腹泻病毒（BVDV），尚不清楚特异性体液免疫反应的发展是否可以预防BVDV感染。这项研究的目的是评估非细胞病性BVDV从预先感染BVDV的小牛的PBMC中复制和产生传染性病毒的能力，并在体外模型中阐明BVDV对这些细胞的免疫调节作用。通过定量PCR对病毒进行定量，同时通过病毒滴定评估其复制能力和向细胞外环境中脱落。通过膜联蛋白V和碘化丙啶的流式细胞术分析，并通过caspase-3 / 7的表达来评估细胞凋亡。流式细胞仪用于分析CD14 / CD11b / CD80，CD4 / CD8 / CD25，MHC-I / MHC-II和B-B2标记。我们的结果表明，自然感染BVDV的牛的PBMC与体外BVDV相比更易受体外BVDV感染，并显示出更严重的凋亡反应。非细胞病性BVDV体外感染也导致抗原呈递表面标志物的表达缺乏影响。所有这些发现可能与BVDV的免疫抑制能力以及牛对这种感染的敏感性有关。