不同攻毒剂量对评估H9亚型禽流感疫苗免疫效果的影响

摘要

To investigate the influence of different referential challenge doses to immunity efficacy evaluation of H9 subtype avian influenza virus (AIV) vaccines,21-day-old specific pathogen free (SPF) chickens were intramuscularly vaccinated with inactivated vaccines prepared from AIVs of CK/HuN/174/08 and CK/HuB/S4196/09 and intranasally challenged by the two virus with referential dose of EID50 and CID50 to compare their influence to efficacy evaluation of the H9 subtype vaccines.The HI antibody results showed that both vaccines of CK/HuN/174/08 and CK/HuB/S4196/09 induced the high HI antibody titers above 10log2 in the 3rd week post vaccination.The EID50 and CID50 per 0.1 mL were 10-9.25 and 10-3.88 for CK/HuN/174/08 and were 10-8.68 and 10-5.38 for CK/HuB/S4196/09,which concluded that EID50 and CID50 were not accordance.The protective rate of vaccines CK/HuN/174/08 and CK/HuB/S4196/09 were 100％ and 0,100％ and 80％,60％ and 0,when challenged with 106 EID50,10 CID50,and 102 CID50,respectively.The results show that the challenge referentially with EID50 and CID50,vaccine CK/HuN/174/08 could completely protect chickens from virus while vaccine CK/HuB/S4196/09 showed different outcomes.In this study,we explained that both EID50 and CID50 could be the challenge reference of H9 subtype avian influenza vaccine efficacy evaluation,but CID50 is more credible than EID50,and the most ideal challenge dose is 10 CID50.We offered a scientific reference for the assessment of H9 subtype avian influenza vaccine immunization efficacy,which has guiding significance for the choice of both vaccine strain and effective vaccines in clinic when study about vaccines.%为了解不同攻毒剂量对评估H9亚型禽流感疫苗免疫效果的影响,本研究选取禽流感病毒(AIV)CK/HuN/174/08和CK/HuB/S4196/09株制备成灭活疫苗免疫21日龄SPF鸡,免疫后采血检测血凝抑制(HI)抗体,免疫后3周时分别采用这两株亲本病毒经鼻腔途径攻毒.HI抗体测定结果显示:两株疫苗免疫21 d时,平均HI抗体滴度均可达10 log2以上,表明这两株病毒均具有良好的免疫原性.测定每0.1 mL CK/HuN/174/08株病毒EID50和CID50分别为10-9.25和10-3.88,CK/HuB/S4196/09株为10-8.68和10-5.38.分别以106 EID50、10 CID50及102 CID50剂量攻毒,CK/HuN/174/08株和CK/HuB/S4196/09株疫苗对亲本病毒株攻击的保护率分别为100％和0、100％和80％与60％和0,表明依据EID50和CID50攻毒,CK/HuN/174/08株疫苗可以得出免疫保护效果一致的结论,而CK/HuB/S4196/09株疫苗免疫保护效果不一致.本研究表明,EID50和CID50均可以作为H9亚型禽流感疫苗攻毒剂量的参考依据,但以CID50为依据更可靠;10 CID50是最佳的攻毒剂量.本研究为科学评价H9亚型禽流感疫苗的攻毒保护效果提供了依据,对于研制疫苗时选择种毒株以及临床上选用有效疫苗均具有指导意义.