聊城大學農學院李旭勇博士課題組在禽流感病毒自然重組研究取得新進展

近日，國際著名期刊《Veterinary Microbiology》刊登了聊城大學農學院李旭勇博士課題組在禽流感病毒研究取得的最新進展。禽流感病毒是一類嚴重危害養殖業和威脅人類健康的人獸共患病病原。作為兩種主要的低致病性禽流感病毒，H4和H9亞型病毒在世界各地陸生家禽和水禽流行廣泛。但由於低致病性流感病毒感染禽類後不表現出明顯的臨床癥狀，使其在自然界長期「沉默」的複製、進化和重組而不易被發現。在自然界中，多種因素使得流行廣泛的H4和H9亞型禽流感病毒共同感染同一宿主的機率顯著增加。

聊城大學研究人員與中國農業科學院哈爾濱獸醫研究所和青島農業大學研究人員合作發現，以不同方式將H4N6和H9N2兩種病毒共同感染雞後，病毒在雞體內發生頻繁的基因重排並通過呼吸道和泄殖腔往外界排出病毒。同時研究人員對從樣品分離純化獲得的病毒進行了生物學特性評估，發現PA基因對重組病毒的複製和毒力有重要影響。

該研究揭示了自然界禽流感病毒共流行和共感染可以促進流感病毒的基因重排，首次闡明了雞在禽流感病毒基因重排中所扮演的重要角色。研究成果以論文形式發表於最新一期《Veterinary Microbiology》上（獸醫學1區），論文查閱網址為https://www.sciencedirect.com/science/article/pii/S0378113517314669。該研究得到了國家自然科學基金、山東省自然科學基金和獸醫微生物國家重點實驗室開放基金的資助。李旭勇博士為本文第一作者，李旭勇博士、郭晶博士和陳化蘭研究員為本文共同通訊作者。

Highlights

High frequency ofreassortmentwas detected afterco-infectionof chickens with the H4N6 andH9N2avian influenzaA viruses.

Nine reassortants were purified successfully from the co-infection samples and their biological properties were evaluated. The H4N6 wtoriginated PA gene plays important role in the enhanced polymerase activity ofRNP complexand the increased replication and virulence of the reassortants in vitro and vivo.

Reassortment during co-infection with different subtypeinfluenzaviruses in chickens is most likely a major feature and plays an important role in the evolution and mutation of theinfluenza A virus.

Abstract

H4 and H9 avian influenza viruses (AIVs) are two of the most prevalent influenza viruses worldwide. The co-existence of H4 and H9 viruses in multiple avian species provides an opportunity for the generation of novel reassortants and for viral evolution. The diversity of the biological characteristics of the reassortants enhances the potential threat to the poultry industry and to public health. To evaluate the reassortment of these viruses and the potential public risk of the reassortants, we co-infected chickens with H4N6 and H9N2 viruses derived from poultry and tested the replication and virulence of the reassortant viruses in mice. A high frequency of reassortment was detected in chickens after co-infection with these two viruses and nine reassortants of six genotypes were purified from the chicken samples. Two H9N2 reassortants containing the PA of the parent H4N6 virus showed higher virulence than the parent H9N2 virus, revealing the significant role of the H4N6 wt virus PA gene in viral reassortment. Analysis of the polymerase activity of the ribonucleoprotein (RNP) complex in vitro suggested that the PA of H4N6 wt origin enhanced polymerase activity. Our results indicate that co-infection of an avian individual with the H4N6 and H9N2 viruses leads to a high frequency of reassortment and generates some reassortants that have higher virulence than the wild-type viruses in mammals. These results highlight the potential public risk of the avian influenza reassortants and the importance of surveillance of the co-existence of the H4N6 and H9N2 viruses in avian species and other animals.

來源：聊城大學

本期編輯：Tony

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