An early pseudorabies virus protein down-regulates porcine MHC class I expression by inhibition of transporter associated with antigen processing (TAP)
An early pseudorabies virus protein down-regulates porcine MHC class I expression by inhibition of transporter associated with antigen processing (TAP)
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DOI：
10.4049/jimmunol.164.1.93
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发表时间：
2000-01-01
影响因子：
4.4
通讯作者：
Srikumaran, S
中科院分区：
文献类型：
--
作者：
Ambagala, APN;Hinkley, S;Srikumaran, S
本研究的目的是确定伪狂犬病病毒(伪狂犬病病毒)诱导猪I类分子下调的机制(S)以及与此相关的病毒蛋白(S)。体外转运试验测定PRV干扰TBP TVAs多肽转运活性的能力。在本实验中，猪肾(PK-15)细胞被链溶素-O通透，并与内质网(ER)中具有一致糖基化作用的I-125标记多肽文库孵育。通过将内质网糖基化的多肽吸附到ConA偶联的琼脂糖球上，确定了多肽从胞浆到内质网的转运效率。在PRV感染的PK-15细胞中，TAP活性呈剂量依赖性抑制。这种抑制最早发生在感染后2小时(H.P.I.)，在感染后6小时达到最高水平，这表明TAP抑制是PRV下调猪I类分子的机制之一。在新陈代谢抑制剂存在的情况下，PRV感染细胞发现，蛋白质合成抑制剂放线菌酮能恢复细胞表面I类分子的表达，而疱疹病毒DNA合成抑制剂磷酸不能恢复细胞表面I类分子的表达，表明晚期蛋白不是下调的原因。在放线菌素D作用下，放线菌素D诱导的即刻早期蛋白的表达不能下调I类分子的表达，表明一个或多个早期蛋白负责下调I类分子的表达。
The objectives of this study were to identify the mechanism(s) of pseudorabies virus (PrV)-induced down-regulation of porcine class I molecules and the viral protein(s) responsible for the effect. The ability of PrV to interfere with the peptide transport activity of TBP tvas determined by an in vitro transport assay. In this assay, porcine kidney (PK-15) cells were permeabilized with streptolysin-O and incubated with a library of I-125-labeled peptides having consensus moths for glycosylation in the endoplasmic reticulum (ER). The efficiency of transport of peptides from the cytosol into the ER was determined by adsorbing the ER-glycosylated peptides onto Con A-coupled Sepharose beads. Dose-dependent inhibition of TAP activity was observed in PrV-infected PK-15 cells. This inhibition,,which occurred as early as 2 h postinfection (h.p.i.), reached the maximum level by 6 h.p.i., indicating that TAP inhibition is one of the mechanisms by which PrV down-regulates porcine class I molecules. Infection of cells with PrV in the presence of metabolic inhibitors revealed that cycloheximide a protein synthesis inhibitor, but not phosphonoacetic acid a herpesvirus DNA synthesis inhibitor, could restore the cell surface expression of class I molecules, indicating that late proteins are not responsible for the down-regulation. Infection in the presence of cycloheximide followed by actinomycin-D, which results in accumulation of the immediate-early protein, failed to down-regulate class I, indicating that one or more early proteins are responsible for the down-regulation of class I molecules.