Abstract：
Classical Swine Fever (CSF) is still one of the most economically important viral diseases of pigs. The disease is controlled by vaccination in the endemic countries. Hence, availability or supply of efficacious and potent vaccine in the field settings is of utmost importance. Currently, as per requirement of any Pharmacopoea, a CSF vaccine must contain 100 PD50/dose which is determined by vaccinating pigs at 1/40th and 1/160th dilution of each dose followed by virulent challenge at 28 days post vaccination (dpv). Here, the control and the unprotected groups succumb to disease and need to be euthanized. Moreover, such challenge experiments are not feasible for each batch of the vaccine. In this communication, an alternate method of PD50 dose calculation of live-attenuated CSF vaccines by measuring Serum Neutralizing Titre i.e Fluorescent Antibody Virus Neutralization (FAVN) titre of the vaccinated pigs at 28 dpv was established. This alternative method do not require the vaccinated pigs to be challenged. Serum samples, generated out of QC testing of eight batches of CSF vaccines in the laboratory, were tested and found that pigs having FAVN titre ≥10 were protected against challenge. Initially this test was optimized in serum samples of 12 animals and then validated with another 56 serum samples. It was found that the alternate method is 100% correlating with the challenge experiment. Thus, based on FAVN titre of the vaccinated animal serum, it can be predicted whether the pigs would or would not come through the challenge infection. Using the predicted status (protected/succumbed), PD50 can be calculated by applying Reed and Muench formula, hence alternate method can be used as routine QC test for potency of CSF vaccines. The newly developed assay was specific since no signal was observed in controls.
摘要：
猪瘟（CSF）仍然是经济上最重要的猪病毒性疾病之一。该疾病在流行国家通过疫苗接种得到控制。因此，在现场环境中有效和有效的疫苗的可用性或供应是至关重要的。目前,根据任何药典的要求，CSF疫苗必须含有100PD50/剂,其通过以每个剂量的1/40和1/160稀释度对猪进行疫苗接种,然后在疫苗接种后28天(dpv)进行毒力攻击来确定。这里,对照组和未受保护的群体死于疾病，需要安乐死。此外，这种攻击实验对每批疫苗都不可行。在这份通讯中,通过在28dpv下测量接种猪的血清中和滴度,即荧光抗体病毒中和(FAVN)滴度,建立了另一种计算减毒CSF活疫苗PD50剂量的方法.该替代方法不需要对接种疫苗的猪进行攻击。血清样本,在实验室对八批CSF疫苗进行质量控制测试后产生，进行了测试，发现FAVN滴度≥10的猪受到了攻击的保护。最初在12只动物的血清样品中优化该测试,然后用另外56份血清样品验证。发现替代方法与攻击实验100%相关。因此，基于接种动物血清的FAVN滴度，可以预测猪是否会受到攻击感染。使用预测状态（受保护/屈服），PD50可以通过应用Reed和Muench公式来计算，因此，替代方法可以用作CSF疫苗效力的常规QC测试。新开发的测定是特异性的,因为在对照中未观察到信号。
