雏鸭重组禽流感(H5+H7)三价灭活苗母源抗体消长规律

Dynamic Changes of Maternal Antibodies Produced in Ducklings by Recombinant AI(H5+H7)Trivalent Inactivated Vaccines

为探究雏鸭重组禽流感(H5+H7)三价灭活苗母源抗体消长规律,确定最佳首免日龄,将试验分为A组(种鸭免疫H5N1 Re-11+Re-12株、H7N9 H7-Re-2株、H5N2疫苗)和B组(种鸭免疫H5N2 rSD57株+rFJ56株、H7N9 rGD76株疫苗);选其孵化后的雏鸭各300羽,分别于1、7、14、21、28日龄时采血,每组随机采集100份样品,通过血凝(HA)和血凝抑制(HI)试验进行禽流感母源抗体检测。结果显示:两组各亚型母源抗体在1日龄时平均滴度均达最高水平(>7.27log2),且离散程度低(>0.22)。两组雏鸭的禽流感母源抗体阳性率均随日龄增长而逐渐下降,7日龄时,平均滴度在4.26log2以上,群体抗体阳性率在76%以上,其中B组阳性率略高于A组;14日龄时,平均滴度都下降到2.55log2以下,群体抗体阳性率下降到25%以下;21日龄时,平均滴度均在0.43log2以下,群体抗体阳性率下降至1%以下。结果表明,高抗体水平种鸭能够使后代雏鸭具有较高水平的禽流感母源抗体,但母源抗体保护时间较短,重组禽流感(H5+H7)三价灭活苗的最佳首免时间为7~14日龄。本研究为鸭禽流感疫苗免疫策略制定提供了参考。

In order to identify dynamic changes of maternal antibodies produced in ducklings when breeding ducks were immunized with recombinant avian influenza(AI)(H5+H7)trivalent inactivated vaccines,and to determine the best day-old for first vaccination,breeding ducks were divided into group A(vaccinated with H5N1 Re-11+Re-12,H7N9 H7-Re-2 and H5N2 vaccines)and group B(vaccinated with H5N2 rSD57+rFJ56 and H7N9 rGD76 vaccines);300 ducklings respectively from each group hatched therefrom were selected to collect blood samples at the ages of 1,7,14,21 and 28 days,successively,then 100 blood samples were randomly collected from each group to detect AI maternal antibodies by hemagglutination assay(HA)and hemagglutination inhibition(HI)assay.The results showed that,for the two groups,the average titer of maternal antibodies of each subtype reached maximum(>7.27log2)at the age of 1 day old,and the level of dispersion was low(>0.22).The positive rates of maternal antibodies of the two groups gradually decreased with the increasing day-old,at the age of 7 days,the average titers were more than 4.26log2,the positive rates of antibodies at group level were above 76%,and higher in group B compared to group A;at the ages of 14 days,both the average titers decreased to less than 2.55log2,and the positive rates of antibodies at group level dropped to less than 25%;at the ages of 21 days,both the average titers decreased to less than 0.43log2,and the positive rates of group antibody dropped to less than 1%.It was concluded that the breeding ducks with high level of antibodies could make their offspring carry AI maternal antibodies at higher level,which,however,lasted for a short time,and the best time for first vaccination with recombinant AI(H5+H7)trivalent inactivated vaccines was at the ages of 7 to 14 days.Some references were thereby provided for the development of measures for vaccination with duck AI vaccines.