Proteins and nucleic acids from ultrasonically ruptured white spot syndrome virus (WSSV) can infect crayfish and cause death as effectively as intact WSSV virions. In this study, ultrasound was used to rupture the virus and the resulting suspension was filtered through a 50 nm membrane. Analysis by PCR and SDS-PAGE showed that both viral genes (VP19, VP26, VP28 and DNA polymerase) and proteins (VP15, VP19, VP26 and VP28) were present in the filtered solution. Electron microscopy showed that there were no intact virions in the filtered solution. When crayfish were injected with the filtered solution or with intact WSSV, the mortality in each group was 100 %. The same result was seen when crayfish were challenged orally with the filtered solution and intact WSSV. The filtered solution of ultrasonically ruptured virus, which contains viral proteins and residual DNA genome, can thus infect the host as effectively as intact virions. When the solution of viral proteins and residual DNA genome was digested with DNase I and then injected into crayfish, the survival rate was 100 %. We also found that, although viral proteins (except VP15) in the solution of ruptured virus were destroyed by treatment with DNase I, DNase I did not destroy the structural proteins of intact virions. A remaining viral protein in the DNase I-treated solution protects the DNA genome from degradation and we concluded that this protein is VP15, which is a DNA-binding protein. Our study highlights the extreme danger in producing vaccines from proteins obtained by ultrasonic rupture of viruses sincethe viral DNA genome is difficult to degrade and, if present, will lead to viral infection.

超声波断裂的白斑综合症病毒（WSSV）的蛋白质和核酸可以感染小龙虾，并像完整的WSSV病毒粒子一样有效地导致死亡。在这项研究中，使用超声波破碎病毒，然后将所得悬浮液通过50 nm膜过滤。通过PCR和SDS-PAGE分析表明，在过滤的溶液中同时存在病毒基因（VP19，VP26，VP28和DNA聚合酶）和蛋白质（VP15，VP19，VP26和VP28）。电子显微镜显示过滤后的溶液中没有完整的病毒体。当向小龙虾注射过滤液或完整的WSSV时，每组的死亡率均为100％。当小龙虾经过滤溶液和完整的WSSV口服刺激后，结果相同。超声破裂病毒的过滤溶液，因此，含有病毒蛋白和残留DNA基因组的病毒可以像完整病毒粒子一样有效地感染宿主。用DNase I消化病毒蛋白和残留DNA基因组的溶液，然后注入小龙虾，成活率为100％。我们还发现，尽管破裂病毒溶液中的病毒蛋白（VP15除外）通过DNase I处理而被破坏，但DNase I并未破坏完整病毒体的结构蛋白。经DNase I处理的溶液中残留的病毒蛋白可保护DNA基因组免于降解，我们得出的结论是该蛋白是VP15，它是一种DNA结合蛋白。我们的研究强调了用病毒超声波破裂获得的蛋白质生产疫苗的极端危险，因为病毒DNA基因组很难降解，并且如果存在，将导致病毒感染。