Dunlap R C
Appl Microbiol. 1970 Apr;19(4):689-93. doi: 10.1128/am.19.4.689-693.1970.
Calf lymph smallpox vaccines contain too much extraneous debris for an accurate assessment of their virus particle content. The process of partial purification of the vaccine utilizing enzymatic digestion by chymotrypsin, subtilisin, and collagenase solubilized enough debris to permit electron microscopic virus particle count. Enzyme treatment did not degrade or destroy the virus nor did it reduce the infective titer. Commercial vaccines studied ranged in virus content from 1.89 x 10(9) to 1.09 x 10(11) virus particles/ml. The pocking efficiencies on the chorioallantoic membrane of some of these vaccines varied from 200 to 1,200 virus particles per pock-forming unit.
小牛淋巴天花疫苗含有过多的外来杂质，无法准确评估其病毒颗粒含量。利用胰凝乳蛋白酶、枯草杆菌蛋白酶和胶原酶进行酶消化对疫苗进行部分纯化的过程，溶解了足够多的杂质，从而能够进行电子显微镜下病毒颗粒计数。酶处理并未降解或破坏病毒，也未降低感染滴度。所研究的商业疫苗的病毒含量范围为每毫升1.89×10⁹至1.09×10¹¹个病毒颗粒。其中一些疫苗在绒毛尿囊膜上的痘疱形成效率为每痘疱形成单位200至1200个病毒颗粒。
