重组禽流感病毒灭活疫苗(H9N2亚型,Re-9株)对2010年～2011年流行病毒株免疫效力的研究

The immune efficacy of the H9N2 avian influenza ressortant virus Re-9 strain inactivated vaccine

为评价H9N2亚型重组禽流感病毒(AIV)灭活疫苗Re-9株的免疫效力,本研究选取2010年～2011年分离的5株H9N2亚型AIV进行攻毒保护实验。这5个分离株均为类A/CK/Beijing/1/94病毒株,其HA和NA基因与Re-9株及其亲本株的同源性介于90.6%～97.5%和88.1%～98.7%之间,其抗原相关值在66.67%～100%之间。将Re-9株为种毒制备灭活疫苗,免疫4周龄SPF雏鸡后,3周时平均HI抗体效价达9.5 log2;在免疫后3周以2×107EID50的剂量攻击亲本株和5株流行病毒株,攻毒后采集3 d、5 d、7 d的拭子,免疫组拭子样品病毒检测均为阴性;对照组3 d、5 d拭子病毒检测的阳性率均在80%以上,7 d的阳性率在60%以下。以上结果表明灭活疫苗Re-9株抗原针对性强,而且具有良好的免疫效力,能够抵御近年来分离的H9N2亚型AIV,是理想的H9N2亚型禽流感疫苗株。

To evaluate the immune efficacy of the vaccine strain Re-9 ressortant avian influenza virus （AIV） derived from H9N2 AIV, the 7-week-old SPF chicks was immunized with Re-9 inactivated vaccine and challenged, respectively, at 3 weeks post immunization with 5 isolates of H9N2 AIV isolated from 2010 to 2011 which the homologous of the HA and NA gene were 90.6% to 97.5% and 88.1% to 98.7%, and the antigen correlation value was 66.67% to 100% with Re-9 strain, respectively. The results showed that the average antibody titer of the HI was up to 9.5 log2 at 3 weeks post immunization. In addition, the virus shedding was detected by virus isolations with chicken embryonated eggs from the trachea and cloaca swab samples collected at 3, 5 and 7 days post challenging, and virus shedding was all negative in the Re-9 vaccinated vaccine groups, but the positive rates in the control groups were higher than 80% at 3 and 5 days, and lower than 60% at 7 days post challenge, respectively. These results demonstrated that the inactivated vaccine prepared with Re-9 strain is high efficient against H9N2 AIV infection.