Osborn T W
J Hyg (Lond). 1980 Oct;85(2):235-46. doi: 10.1017/s0022172400063270.
Changes in the Danish BCG strain under certain regimens of subculture have been shown in preceding studies to be associated with selection of a minority population. Three Czechoslovakian BCG strains, all originally derived from the Danish strain but thereafter and in distinction from it maintained on potato media, have now been investigated. Changes in the immunizing potency of two of these strains have been attributed by other workers to employment of the richer potato media in place of Sauton medium as used for maintenance of the parent Danish strain. However, results from the present study suggest rather that selection of a pre-existing minority genotype or of a new mutant occurred. This proposal is supported by the finding that the third strain has maintained characteristics similar to those of the Danish parent despite many previous transfers on potato media.Another BCG strain investigated was the Japanese which, like the three Czechoslovakian strains, had been previously maintained on potato media. This strain has been shown in the present study to resemble the Danish strain in supporting a minority population yielding non-spreading colonies. Czechoslovakian vaccine prepared with seed culture supplied from Tokyo has retained characteristics similar to those of the Japanese parent. Although a majority population yielding spreading colonies appears so far to have been retained in both centres, it is considered that selection of the minority could still occur in the course of routine transfer.
在之前的研究中已表明，丹麦卡介苗菌株在特定传代培养方案下的变化与少数群体的选择有关。现已对三种捷克斯洛伐克卡介苗菌株进行了研究，这三种菌株最初均源自丹麦菌株，但此后在马铃薯培养基上进行培养，与丹麦菌株有所不同。其他研究人员将其中两种菌株免疫效力的变化归因于使用了营养更丰富的马铃薯培养基，而非用于保存亲本丹麦菌株的苏通培养基。然而，本研究结果表明，更有可能是预先存在的少数基因型或新突变体被选择出来。这一观点得到了以下发现的支持：尽管第三种菌株此前在马铃薯培养基上经过多次传代，但仍保持了与丹麦亲本相似的特征。另一种被研究的卡介苗菌株是日本菌株，与三种捷克斯洛伐克菌株一样，此前一直在马铃薯培养基上培养。本研究表明，该菌株在支持产生不扩散菌落的少数群体方面与丹麦菌株相似。用从东京提供的种子培养物制备的捷克斯洛伐克疫苗保留了与日本亲本相似的特征。尽管到目前为止，两个中心似乎都保留了产生扩散菌落的多数群体，但人们认为在常规传代过程中仍可能发生少数群体的选择。
