斑鸠对H9N2亚型禽流感病毒的易感性及其流感病毒受体类型的研究

Study on the Susceptibility of Turtledoves to Avian Influenza Virus Subtype H9N2 and its Receptor

【目的】验证斑鸠对H9N2亚型禽流感病毒的易感性,测定斑鸠呼吸道上皮细胞表面流感病毒受体的类型和分布。【方法】以5×104EID50/只的剂量经滴鼻、点眼途径感染A/Chicken/Beijing/2/2009(H9N2)亚型禽流感病毒,共感染8只斑鸠和8只SPF鸡,对试验斑鸠和SPF鸡进行临床症状、大体病变、组织学病变的观察及病毒抗原的定位、病毒分离和感染抗体的测定。【结果】攻毒后5d,斑鸠和SPF鸡未见异常临床表现和大体病变,病理组织学检查发现斑鸠的喉头、气管上段、中段和下段上皮细胞均有不同程度的脱落;在斑鸠的喉头、气管上段、中段和下段上皮细胞的胞浆内检测到了大量阳性流感病毒蛋白颗粒;斑鸠咽拭子病毒分离阳性率为75%(6/8),SPF鸡咽拭子病毒分离阳性率为100%(8/8)。攻毒后14d,斑鸠H9N2亚型禽流感病毒HI抗体阳性率为80%(4/5),SPF鸡HI抗体阳性率为100%(5/5)。对H9N2亚型禽流感病毒受体检测结果表明,斑鸠的喉头、气管上段、中段、下段上皮细胞表面存在SAα2,3Gal和SAα2,6Gal两种连接键型的受体。【结论】斑鸠对H9N2亚型禽流感病毒A/Chicken/Beijing/2/2009(H9N2)易感,且斑鸠的喉头和气管上、中、下段上皮细胞表面同时存在能够与禽流感病毒结合的SAα2,3Gal受体和与人流感病毒结合的SAα2,6Gal受体。

【Objective】 The susceptibility of turtledove to H9N2 subtype avian influenza virus and the type and distribution of influenza virus receptors in the respiratory tract epithelium of turtledove were studied.【Method】 Eight turtledoves and eight SPF chickens were inoculated with A/Chicken/Beijing/2/2009 H9N2 via oculonasal routes at a dose of 5×104EID50 per bird.In addition to observation of clinical signs and gross pathological changes and histopathological changes,the location of the viral antigen and antibody detection were used.Influenza A matrix protein was observed by immunohistochemistry straining.The type of SAα2,6Gal and SAα2,3Gal linkage on these animals＇ trachea and larynx epithelium cells were detected by digoxigenin-labeled lectin staining.【Result】 On day 5 post inoculation,no abnomal clinical signs and pathological changes were found in the turtledoves and SPF chickens.The epithelium was found with different degrees of swelling in the turtledove＇ larynx,upper trachea,middle trachea and lower trachea.The virus positive particles were detected in turtledoves＇ upper trachea,middle trachea,lower trachea and lung epithelium with the method of immunohistochemistry;H9N2 AIV was isolated from turtledoves,and the positive rate of turtledoves＇ nasopharyngeal swab was 75%（6/8）,that of SPF chickens＇ was 100%（8/8）.On 14th day post inoculation,HI antibody was detected,and the positive rate of turtledoves＇ was 80%（4/5）,that of SPF chickens was 100（5/5）.SAα2,3Gal and SAa2,6Gal were both detected on turtledove＇s larynx,upper trachea,middle trachea and lower trachea 【Conclusion】 The turtledoves are susceptible to A/Chicken/Beijing/2/2009,and there are both SAα2,3Gal binding avian influenza virus and SAα2,6Gal binding human influenza virus on turtledove＇s larynx,upper trachea,middle trachea and lower trachea.