人類微小病毒B19結構蛋白獨立區域VP1u對巨噬細胞影響之研究

The Effects Of Human Parvovirus B19 VP1Unique Region On Macrophage

施靖瑜(Shih-jing yu)

指導教授 ： 徐再靜

中山醫學大學/醫學院/免疫學研究所/碩士(2008年)

摘要

先前文獻已知人類微小病毒B19 (Human Parvovirus B19，B19) VP1在N端區域有一段結構蛋白獨立區域VP1u，該區域的130-195胺基酸序列上有一段Phospholipase A2 (PLA2) motif，此序列目前已被分類為GroupΧIII sPLA2，但其詳細功能未知。先前文獻報告指出B19-VP1u之sPLA2活性可促進滑膜細胞(Synoviocytes)細胞遷移(Migration)，但是對於先天性免疫細胞之巨噬細胞的影響並不清楚，因此我們進行本篇論文的研究。本研究實驗發現B19-VP1u具有sPLA2的活性而點突變PLA2 motif成為B19-VP1uD175A則會使其sPLA2活性喪失。B19-VP1u之sPLA2的活性不僅可促使老鼠巨噬細胞Raw264.7之細胞遷移，並且可促進巨噬細胞之吞噬能力。此外，B19-VP1u之sPLA2的活性也會增加發炎性細胞激素(IL-6、IL-1β、GM-CSF)之mRNA的表現，並促進MMP9的表現。綜合以上可知人類微小病毒B19-VP1u可以促使巨噬細胞活化進而引起先天性免疫防禦機制的啟動，這些發現將可提供未來對於人類微小病毒B19之預防感染及疫苗開發上的一些線索參考。

關鍵字

人類微小病毒B19

並列摘要

Human Parvovirus B19 (B19) have two structural protein ,VP1 (83KDa) and VP2 (58KDa), which are identical except for 227 amino acids at the amino-terminal end of the VP1-protein, the so-called VP1-unique region (VP1u). Recently, a phospholipase A2 (PLA2) motif was identified in the VP1u and has been classified as group XIII sPLA2, which the mechanism remains unclear. Previous studies have shown that B19-VP1u PLA2 motif can stimulate activation of synoviocytes. However, the effects of B19-VP1u PLA2 motif on initiating innate immunity by macrophages are still unknown. In this study, we found that the purified B19-VP1u proteins had sPLA2 activity but the purified B19-VP1uD175A proteins did not. We also found that B19-VP1u significantly induced mouse macrophage cells RAW264.7 migration and phagocytosis as compared to mutant VP1uD175A proteins and control. In addition, we found that VP1u-PLA2 motif induced the inflammatory cytokine expression, including IL-6, IL-1β, and GM-CSF by multiplex PCR. Moreover, we found that VP1u-PLA2 motif induced the MMP-9 expression. These findings may offer some clue in understanding the effects of macrophage on B19 infection and for vaccine development in the future.

並列關鍵字

Human Parvovirus B19

參考文獻

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