Björklund H V, Stadejek T, Vilcek S, Belák S
Department of Virology, National Veterinary Institute, Uppsala, Sweden.
Virus Genes. 1998;16(3):307-12. doi: 10.1023/a:1008095109033.
The genomes of classical swine fever virus (CSFV) vaccine strains are poorly characterized, and the mechanisms for their attenuation remain unknown. The aim of the present study was to characterize the 3' noncoding region (3' NCR) of a number of attenuated vaccine strains of CSFV in order to examine changes in the viral genome after attenuation. The results showed that the 3' NCR:s of Porcivac, Rovac, Russian LK and original Chinese vaccine strain contain insertions very similar to that present in the published nucleotide sequence of the C-strain. Phylogenetic analysis showed that the vaccine strains Porcivac, Rovac and Russian LK vaccine were closely related to each other, but that these three strains showed a distant relationship with two tested variants of the Chinese vaccine strain (C-strain and original Chinese vaccine). The 3' NCR insertion is not likely to be a marker for attenuation of the virus, since many CSFV vaccine strains do not contain the insertion. The fact that the insertions occur in lapinized vaccine strains suggests that these genetic segments were incorporated during the adaptation of the virus to the rabbit host system.
经典猪瘟病毒（CSFV）疫苗株的基因组特征尚不明确，其减毒机制也仍然未知。本研究的目的是对一些CSFV减毒疫苗株的3'非编码区（3'NCR）进行特征分析，以研究病毒减毒后其基因组的变化。结果表明，Porcivac、Rovac、俄罗斯LK疫苗株以及中国原始疫苗株的3'NCR含有与已发表的C株核苷酸序列中存在的插入片段非常相似的插入片段。系统发育分析表明，Porcivac、Rovac和俄罗斯LK疫苗株彼此密切相关，但这三个毒株与中国疫苗株（C株和中国原始疫苗）的两个测试变体关系较远。3'NCR插入片段不太可能是病毒减毒的标志，因为许多CSFV疫苗株并不包含该插入片段。插入片段出现在兔化疫苗株中的事实表明，这些基因片段是在病毒适应兔宿主系统的过程中整合进去的。
