鸭短喙侏儒综合征亚单位疫苗对鹅细小病毒和番鸭细小病毒的交叉保护力分析

Cross Protection Analysis of Duck Short Beak and Dwarfism Syndrome Subunit Vaccine against Goose Parvovirus and Muscovy Duck Parvovirus

为评价鸭短喙侏儒综合征(SBDS)亚单位疫苗(rBac-JS01 VP2株)对鹅细小病毒(GPV)和番鸭细小病毒(MDPV)的交叉保护力,本试验选用40只产蛋母鸭和4只成年公鸭随机均分成2个组,疫苗免疫组母鸭免疫接种SBDS亚单位疫苗0.5 mL/只,非免疫对照组不作任何处理。免疫后第2、4、6个月,分别收集各组产蛋母鸭鸭蛋并人工孵化,每个时间段任意选择健康的公、母雏鸭各10只,进行GPV-JS02毒株或MDPV-JS03毒株攻毒,在攻毒后第3、5、7、14天采集雏鸭肛拭子检测排毒情况。此外,免疫后第2、4、6个月,所有产蛋母鸭采血并分离血清,收集鸭蛋并提取和纯化卵黄中和抗体,分别采用GPV-JS02毒株或MDPV-JS03毒株测定血清和卵黄中和抗体效价,并比较血清和卵黄中和抗体效价与被动免疫攻毒保护率的关系。结果显示,产蛋母鸭免疫后第2、4、6个月,疫苗免疫组种蛋所孵雏鸭的GPV-JS02毒株攻毒保护率分别为95%、90%和80%,MDPV-JS03毒株攻毒保护率分别为75%、70%和60%;GPV-JS02毒株攻毒后,雏鸭排毒分别持续至攻毒后第3、5、5天,MDPV-JS03毒株攻毒后,雏鸭排毒均持续至攻毒后第7天;产蛋母鸭GPV-JS02毒株的血清中和抗体效价分别为(9.23±1.33)log_(2)、(8.45±1.14)log_(2)和(7.79±1.02)log_(2);MDPV-JS03毒株的血清中和抗体效价分别为(5.93±1.37)log_(2)、(5.15±1.08)log_(2)和(3.48±0.96)log_(2);产蛋母鸭GPV-JS02毒株的卵黄中和抗体效价分别为(9.06±1.3)log_(2)、(8.49±1.08)log_(2)和(7.70±1.01)log_(2),MDPV-JS03毒株的卵黄中和抗体效价分别为(5.83±1.25)log_(2)、(5.34±1.02)log_(2)和(3.71±1.64)log_(2);免疫后不同时期的血清和卵黄中和抗体效价与被动免疫攻毒保护率变化基本一致,升降趋势相同,具有很好的相关性。结果表明,SBDS亚单位疫苗(rBac-JS01 VP2株)对GPV可提供有效且持续的交叉保护力,对MDPV也可提供一定的交叉保护力,但比GPV的保护力略低。

To evaluate the cross-protection of the subunit vaccine(rBac-JS01 VP2 strain) against short beak and dwarfism syndrome(SBDS) in ducks against goose parvovirus(GPV) and muscovy duck parvovirus(MDPV),a study was conducted using 40 laying female ducks and 4 adult male ducks,randomly divided into two groups.The vaccination group was immunized with 0.5 mL of the SBDS subunit vaccine per duck,while the non-immunized control group received no treatment.At 2,4,and 6 months post-immunization,eggs were collected from the laying ducks in each group and artificially incubated.At each time point,10 healthy male and female ducklings were randomly selected and challenged with the GPV-JS02 strain or MDPV-JS03 strain.Cloacal swabs were collected on days 3,5,7,and 14 post-challenge to detect viral shedding in the ducklings.Additionally,at 2,4,and 6 months post-immunization,blood samples were taken from all laying ducks to isolate serum,and egg yolks were collected for the extraction and purification of neutralizing antibodies.The serum and yolk neutralizing antibody titers were determined using the GPV-JS02 or MDPV-JS03 strains,and the relationship between these titers and passive immunity protection rates was analyzed.The results showed that at 2,4,and 6 months post-immunization,the protection rates against the GPV-JS02 strain challenge in ducklings hatched from eggs of the vaccination group were 95%,90%,and 80%,respectively,while the protection rates against the MDPV-JS03 strain challenge were 75%,70%,and 60%,respectively.Viral shedding in the ducklings challenged with the GPV-JS02 strain persisted until days 3,5,and 5 post-challenge,respectively,while viral shedding in those challenged with the MDPV-JS03 strain persisted until day 7 post-challenge.The serum neutralizing antibody titers against the GPV-JS02 strain were( 9.23 ± 1.33) log2,( 8.45 ±1.14) log2,and( 7.79 ± 1.02) log2,respectively,while the titers against the MDPV-JS03 strain were( 5.93 ±1.37) log2,( 5.15 ±1.08) log2,and( 3.48 ± 0.96) log2,respectively.The yolk neutralizing antibody titers against the GPV-JS02 strain were( 9.06 ±1.3) log2,( 8.49 ± 1.08) log2,and( 7.70 ± 1.01) log2,respectively,while the titers against the MDPV-JS03 strain were( 5.83 ±1.25) log2,( 5.34 ± 1.02) log2,and( 3.71 ± 1.64) log2,respectively.The changes in serum and yolk neutralizing antibody titers over different periods were consistent with the changes in passive immunity protection rates,showing similar trends and good correlation.The results indicate that the SBDS subunit vaccine( r Bac-JS01 VP2 strain) provides effective and lasting cross-protection against GPV and some degree of cross-protection against MDPV,although the protection against MDPV is slightly lower than that against GPV.