美國研究人員在新一期《實驗醫學雜志》上報告說，他們在研究2009年暴發的甲型H1N1流感時發現，感染過這種流感的人體內會產生抵御其他多種流感病毒的抗體，這一發現有可能幫助科學家研制出新的抗流感疫苗。

一個由埃默里大學醫學院和芝加哥大學的科學家組成的研究小組對9名志愿者進行研究，得出了上述結論。這9名志愿者多數是20歲至30多歲的年輕人，都在2009年甲型H1N1流感疫情蔓延期間受到感染。在發現癥狀之后10天，醫院對他們進行抽血并保留樣本。

在這些志愿者體內，研究人員發現了一種普通流感患者或者注射過普通流感疫苗的人所沒有的免疫反應。這種反應所產生的抗體，能保護機體免受過去10年所發現的全部季節性H1N1型病毒的侵害，同時還能抵御1918年“西班牙流感”病毒，以及H5N1型禽流感病毒的感染。

研究人員先從這些志愿者的血液樣本中找到能產生抗體的白細胞，從中分離出抗體基因，然后利用這些抗體基因在實驗室中培育出86種抗體。研究人員接著對這些抗體進行試驗，以確定它們究竟能抵御哪種流感病毒。

研究發現，有5種抗體具有交叉保護作用，能抵御上述多種流感病毒和H5N1型禽流感病毒。

在實驗鼠身上使用這些抗體進行試驗的結果顯示，實驗鼠得到全面保護，可免受致病劑量流感病毒的侵襲。

研究人員指出，新的研究成果表明，如果對免疫系統進行正確的刺激，可促使人體產生新的流感抗體，這意味著科學家今后有可能研制出能有效抵御多種流感病毒的疫苗。

推薦原文出處：

The Journal of Experimental Medicine   doi: 10.1084/jem.20101352

Broadly cross-reactive antibodies dominate the human B cell response against 2009 pandemic H1N1 influenza virus infection

Jens Wrammert1,2, Dimitrios Koutsonanos2, Gui-Mei Li1,2, Srilatha Edupuganti4,5, Jianhua Sui6, Michael Morrissey8, Megan McCausland1,2, Ioanna Skountzou2, Mady Hornig9, W. Ian Lipkin9, Aneesh Mehta3, Behzad Razavi5, Carlos Del Rio3,4,10, Nai-Ying Zheng8, Jane-Hwei Lee8, Min Huang8, Zahida Ali8, Kaval Kaur8, Sarah Andrews8, Rama Rao Amara1,2, Youliang Wang1, Suman Ranjan Das11, Christopher David O'Donnell12, Jon W. Yewdell11, Kanta Subbarao12, Wayne A. Marasco6, Mark J. Mulligan4, Richard Compans1, Rafi Ahmed1,2, and Patrick C. Wilson8

Abstract

The 2009 pandemic H1N1 influenza pandemic demonstrated the global health threat of reassortant influenza strains. Herein, we report a detailed analysis of plasmablast and monoclonal antibody responses induced by pandemic H1N1 infection in humans. Unlike antibodies elicited by annual influenza vaccinations, most neutralizing antibodies induced by pandemic H1N1 infection were broadly cross-reactive against epitopes in the hemagglutinin (HA) stalk and head domain of multiple influenza strains. The antibodies were from cells that had undergone extensive affinity maturation. Based on these observations, we postulate that the plasmablasts producing these broadly neutralizing antibodies were predominantly derived from activated memory B cells specific for epitopes conserved in several influenza strains. Consequently, most neutralizing antibodies were broadly reactive against divergent H1N1 and H5N1 influenza strains. This suggests that a pan-influenza vaccine may be possible, given the right immunogen. Antibodies generated potently protected and rescued mice from lethal challenge with pandemic H1N1 or antigenically distinct influenza strains, making them excellent therapeutic candidates.

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