Ⅰ群禽腺病毒(4型)Fiber-2蛋白亚单位疫苗与全病毒灭活疫苗的免疫效果比较

Comparison of Immune Effect with Subunit Vaccine for Fiber-2 Protein Fowl Adenovirus Serotype 4 of Group I and Whole Virus Inactivated Vaccine

为了比较不同抗原含量的Ⅰ群禽腺病毒(4型)Fiber-2蛋白亚单位疫苗与全病毒灭活疫苗的免疫效力差异,本研究制备不同抗原含量的亚单位疫苗和全病毒灭活疫苗,采用超低免疫剂量20μL/只免疫SPF鸡,免疫21 d后攻毒,通过死亡率、临床症状、大体剖检病变、免疫组化和泄殖腔拭子排毒等进行免疫效力比较。试验结果表明,亚单位疫苗抗原含量AGP效价不低于1∶8,全病毒灭活疫苗抗原含量为10^(7.0)TCID_(50)/0.1 mL时,可抵抗Ⅰ群禽腺病毒(4型)强毒株的攻击,提供100%的免疫攻毒保护,攻毒后3、5、7 d泄殖腔拭子均未见排毒,且免疫组化均为阴性。亚单位疫苗抗原含量AGP效价为1∶4,全病毒灭活疫苗抗原含量为106.5 TCID_(50)/0.1 mL时,在超低免疫剂量情况下,仍可提供至少80%的免疫攻毒保护,且攻毒后3、5、7 d泄殖腔拭子排毒率仅为2/10~3/10,免疫组化阳性率仅为1/10。但全病毒灭活疫苗抗原含量为106.0 TCID_(50)/0.1 mL时,免疫攻毒保护效果不理想。综合以上结果表明,Fiber-2蛋白具有良好的免疫原性,抗原含量AGP效价不低于1∶4,与全病毒灭活疫苗抗原含量为106.5 TCID_(50)/0.1 mL免疫效力相当,可用于疫苗研制开发。

In order to compare the difference of immune efficacy between Group I Avian adenovirus(type 4)Fibre-2 protein subunit vaccine and whole virus inactivated vaccine with different antigen content,this study prepared subunit vaccine and whole virus inactivated vaccine with different antigen content,immunized SPF chicken with ultra-low immune dose of 20μL/bird,and challenged for 21 days after immunization.The immune efficacy was compared by mortality,clinical symptoms,gross biopsy,immunohistochemistry and cloacal swab detoxification.The results showed that when the subunit vaccine antigen content AGP titer was no less than 1∶8 and the whole virus inactivated vaccine antigen content was 10^(7.0)TCID_(50)/0.1mL,it could resist the attack of Group I avian adenovirus(type 4)strong strain and provide 100%immune challenge protection.No detoxification was observed in cloacal swabs 3,5,7 days after challenge.The results of immunohistochemistry were negative.When the subunit vaccine antigen content AGP was 1∶4 and the whole virus inactivated vaccine antigen content was 106.5 TCID_(50)/0.1mL,it could still provide at least 80%immune challenge protection under the condition of ultra-low immune dose,and the detoxification rate of cloacal swab was only 2/10~3/10 after 3,5 and 7 days of challenge.The immunohistochemical positive rate was only 1/10.However,when the antigen content of whole virus inactivated vaccine was 106.0 TCID_(50)/0.1mL,the immune challenge protection effect was not ideal.The above results showed that Fiber-2 protein had good immunogenicity,and the AGP titer of the antigen content was no less than 1∶4,which was equivalent to the immune efficacy of the whole virus inactivated vaccine with the antigen content of 106.5 TCID_(50)/0.1mL,and could be used for vaccine development.