Panaiotov Stefan, Hodzhev Yordan, Tolchkov Vladimir, Tsafarova Borislava, Mihailov Alexander, Stefanova Tzvetelina
National Center of Infectious and Parasitic Diseases, 1504 Sofia, Bulgaria.
BB-NCIPD Ltd., 1504 Sofia, Bulgaria.
Vaccines (Basel). 2021 Mar 9;9(3):237. doi: 10.3390/vaccines9030237.
bacillus Calmette-Guérin (BCG) is the only live attenuated vaccine available against tuberculosis. The first BCG vaccination was done exactly 100 years ago, in 1921. The BCG vaccine strains used worldwide represent a family of daughter sub-strains with distinct genotypic characteristics. BCG SL222 Sofia is a seed lot sub-strain descending from the Russian BCG-I (seed lot 374a) strain and has been used for vaccine production in Bulgaria since 1972. Here, we report the assembled circular genome sequence of BCG SL222 Sofia and phylogeny analysis with the most closely related BCG sub-strains. The full circular genome of BCG SL222 Sofia had a length of 4,370,706 bp with an average GC content of 65.60%. After 49 years of in vitro evolution in a freeze-dried condition, we identified four SNP mutations as compared to the reference BCG-I (Russia-368) sequence. BCG vaccination is of central importance for the TB elimination programs in many countries. Since 1991, almost 40 million vaccine doses of the BCG SL222 Sofia have been distributed annually through the United Nations Children's Fund (UNICEF) and the Pan American Health Organization (PAHO) to approximately 120 countries. The availability of the complete reference genome sequence for BCG SL222 Sofia, a WHO reference reagent for the Russian BCG-I sub-strain, will facilitate the identity assurance of the genomic stability, will contribute to more consistent manufacturing, and has an important value in standardization and differentiation of sub-strains used in vaccine production. We propose to rename the sub-strain BCG SL222 Sofia to BCG-Sofia for practical and common use.
卡介苗（BCG）是唯一可用于预防结核病的减毒活疫苗。首次卡介苗接种恰好在100年前，即1921年进行。全球使用的卡介苗疫苗株代表了一个具有不同基因型特征的子代亚株家族。卡介苗SL222索菲亚株是源自俄罗斯卡介苗-I（种子批374a）株的一个种子批亚株，自1972年以来一直在保加利亚用于疫苗生产。在此，我们报告了卡介苗SL222索菲亚株的环状基因组序列组装以及与最密切相关的卡介苗亚株的系统发育分析。卡介苗SL222索菲亚株的完整环状基因组长度为4,370,706 bp，平均GC含量为65.60%。在冻干条件下经过49年的体外进化后，与参考卡介苗-I（俄罗斯-368）序列相比，我们鉴定出了四个单核苷酸多态性（SNP）突变。卡介苗接种对许多国家的结核病消除计划至关重要。自1991年以来，每年通过联合国儿童基金会（UNICEF）和泛美卫生组织（PAHO）向约120个国家分发近4000万剂卡介苗SL222索菲亚株疫苗。卡介苗SL222索菲亚株作为世界卫生组织俄罗斯卡介苗-I亚株的参考试剂，其完整参考基因组序列的可用性将有助于保证基因组稳定性的鉴定，有助于实现更一致的生产，并且在疫苗生产中使用的亚株标准化和鉴别方面具有重要价值。为了实际和通用起见，我们建议将亚株卡介苗SL222索菲亚株重新命名为卡介苗-索菲亚株。
