RILEY J M, ORLANDO M D
Appl Microbiol. 1964 Jan;12(1):7-9. doi: 10.1128/am.12.1.7-9.1964.
A biological assay for variola virus was needed that would (i) require a minimum of time and (ii) have acceptable precision. Preliminary titrations made in 11-day-old embryonated eggs and in suckling mice (6 to 24 hr of age) demonstrated a linear relationship between the concentration of variola virus injected and the mean reciprocal time to death (MTD) of both hosts. This linear response indicated that the injection of a single dose of virus suspension and the measurement of the MTD should result in an acceptable assay method. Seven replicate samples of liquid preparations (20% chorioallantoic membrane in Heart Infusion Broth) and the freeze-dried material obtained with these suspensions were assayed in triplicate for pock infectious units and for MTD. The variance of the pock counts was far greater than was expected from a Poisson distribution, and coefficients of variation ranged from 25 to 61%. Variances obtained with the single-dilution assay were all far below that expected from a Poisson distribution, and coefficients of variations ranged from 5.2 to 13.6%. The use of the MTD assay resulted in a saving of time, a saving in the number of hosts necessary per assay, and increased precision.
需要一种针对天花病毒的生物学检测方法，该方法应（i）所需时间最短，且（ii）具有可接受的精度。在11日龄的鸡胚和乳鼠（6至24小时龄）中进行的初步滴定表明，注射的天花病毒浓度与两种宿主的平均死亡倒数时间（MTD）之间存在线性关系。这种线性反应表明，注射单剂量病毒悬液并测量MTD应能产生一种可接受的检测方法。对液体制剂（心脏浸液肉汤中20%的绒毛尿囊膜）的七个重复样本以及用这些悬液获得的冻干材料进行了三次重复检测，以确定痘疱感染单位和MTD。痘疱计数的方差远大于泊松分布预期的方差，变异系数范围为25%至61%。单稀释检测获得的方差均远低于泊松分布预期的方差，变异系数范围为5.2%至13.6%。使用MTD检测可节省时间、减少每次检测所需的宿主数量并提高精度。
