高致病性猪繁殖与呼吸综合征活疫苗的研制

Development of an attenuated live vaccine against highly pathogenic porcine reproductive and respiratory syndrome

将高致病性猪繁殖与呼吸综合征病毒致弱株TJM株与耐热冻干保护剂混合制备弱毒活疫苗,并对该活疫苗进行安全性、免疫保护效果和保存期试验。结果显示,4～5周龄仔猪接种该疫苗后体温正常,无任何临床可见异常。该疫苗接种猪对强毒攻击的保护率达4/5以上;将其置于2～8℃保存24个月,病毒效价降低不超过100.5 TCID50/mL。表明该疫苗对猪安全,免疫保护效果良好,且便于保存。

An attenuated highly pathogenic porcine reproductive and respiratory syndrome virus（HP-PRRSV） vaccine was developed by blending the attenuated HP-PRRSV TJM strain with heat endurable protective agent.The safety and efficacy（immunogenicity） in host animals and the period of validity at 2 to 8℃ of the vaccine were tested. In order to test the safety of the vaccine,4 to 5 weeks-old pigs were inoculated with 2mL（106.7TCID50/mL） of the vaccine.In the efficacy study,4 to 5 weeks-old pigs were vaccinated with 1mL of 105.0TCID50 of the vaccine. The animals were challenged with virulent virus on day 28 post-vaccination. To determine the period of validity,the vaccine was sampled on month 3,6,9,12,18,21,and 24 post-vaccination at 2 to 8℃ to test the virus titer. Results revealed that the pigs did not show any clinical diseases post-vaccination.Immunogenicity study demonstrated that the vaccine provided at least four fifths protection to pigs against the HP-PRRSV infection and clinical diseases caused by the challenge.The virus titer decreased no more than 100.5TCID50/mL after 24 month at 2 to 8℃. The results indicated that the vaccine is safe,efficacy to host animals,and easy to be reserved.