Rapid test to detect cytotoxic activity in vaccines against foot-and-mouth disease

ABSTRACT Substances with cytotoxic activity present in vaccines against the foot-and-mouth disease may interfere with methods used to detect residual live virus in the product or cause undesirable postvaccination reactions. This study describes a rapid in vitro test to detect cytotoxic activity in water-in-oil vaccines against foot-and-mouth disease using a commercial saponin as a cytotoxic agent and a solution of sheep’s red blood cells as substrate. Hemolytic and cytotoxic activity was analyzed using experimental and commercial vaccines prepared with and without saponin. The hemolytic and cytotoxic potential of preparations containing saponin was evident. In contrast, hemolytic and cytotoxic activities were not observed in vaccines without saponin in their composition. The method described here allows to easily detect if the vaccine under study has cytotoxic activity, making it possible to select the most appropriate method to process the sample to be used for the innocuity test. Additionally, due to undesirable effects that may be observed in animals receiving vaccines containing saponin in their formulation, the use of the rapid test described here allows to identify those vaccines with cytotoxic activity and to verify the presence of saponin on them, through the mass spectrometry method.摘要 口蹄疫疫苗中含有的细胞毒性活性（cytotoxic activity）物质，可能会干扰产品中残留活病毒的检测方法，或引发不良的疫苗接种后反应。本研究建立了一种快速体外（in vitro）检测方法，用于检测口蹄疫水包油疫苗（water-in-oil vaccine）中的细胞毒性活性：以商业化皂苷（saponin）作为细胞毒性试剂，以绵羊红细胞溶液作为底物。本研究采用添加或未添加皂苷的试验性及商业化疫苗，对其溶血活性与细胞毒性活性进行分析。结果显示，含皂苷的制剂可检测到明显的溶血与细胞毒性潜能；与之相反，组分中不含皂苷的疫苗未观察到溶血与细胞毒性活性。本研究所述方法可便捷检测受试疫苗是否具有细胞毒性，从而能够选择最适宜的方法处理用于安全性试验的样品。此外，鉴于接种含皂苷配方疫苗的动物可能出现不良反应，本研究所述快速检测方法可通过质谱法（mass spectrometry），识别具有细胞毒性的疫苗并验证其中皂苷的存在。