研究人員發(fā)現(xiàn)，血小板在驅(qū)動(dòng)免疫系統(tǒng)對(duì)細(xì)菌作出反應(yīng)的過(guò)程中發(fā)揮了重要作用,，新成果發(fā)表在11月在線出版的《自然—免疫學(xué)》期刊上,。
血小板的經(jīng)典作用是它們參與了血凝反應(yīng)。然而,，Dirk Busch和同事指出,，特定類型的細(xì)菌在血液中會(huì)被血小板迅速包裹，這一過(guò)程依賴于一種血小板所表達(dá)的分子GPIb,。被包裹的細(xì)菌被運(yùn)送到脾臟并在那里被樹突狀細(xì)胞所吞噬,，樹突狀細(xì)胞在免疫系統(tǒng)功能的全面啟動(dòng)中發(fā)揮了重要作用。而未被血小板所包裹的細(xì)菌則被運(yùn)送到巨噬細(xì)胞中,，并在其中被摧毀,，但這一過(guò)程不會(huì)讓身體產(chǎn)生免疫記憶。（生物谷 Bioon.com)
doi:10.1038/ni.2140
PMC:
PMID:
A platelet-mediated system for shuttling blood-borne bacteria to CD8α+ dendritic cells depends on glycoprotein GPIb and complement C3
Admar Verschoor,1, 2, 3 Michael Neuenhahn,1, 4 Alexander A Navarini,2, 7 Patricia Graef,1 Ann Plaumann,1 Amelie Seidlmeier,1 Bernhard Nieswandt,5 Steffen Massberg,6 Rolf M Zinkernagel,2, 8 Hans Hengartner2, 8 & Dirk H Busch1, 3, 4, 8
The acquisition of pathogen-derived antigen by dendritic cells (DCs) is a key event in the generation of cytotoxic CD8+ T cell responses. In mice, the intracellular bacterium Listeria monocytogenes is directed from the blood to splenic CD8α+ DCs. We report that L. monocytogenes rapidly associated with platelets in the bloodstream in a manner dependent on GPIb and complement C3. Platelet association targeted a small but immunologically important portion of L. monocytogenes to splenic CD8α+ DCs, diverting bacteria from swift clearance by other, less immunogenic phagocytes. Thus, an effective balance is established between maintaining sterility of the circulation and induction of antibacterial immunity by DCs. Other Gram-positive bacteria also were rapidly tagged by platelets, revealing a broadly active shuttling mechanism for systemic bacteria.
