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为探讨SLA DR基因结构及其在猪 人异种器官移植中的作用 ,本研究采用RT PCR扩增三个中国猪种SLA DRcDNA ,然后克隆入测序载体 ,进行双向测序 ,获得了具有完整阅读框架的三个结构和已有序列不同的新DRB等位基因 ,其长度为80 1个核苷酸 ,除末端终止密码外 ,编码 2 6 6个氨基酸残基 ;三个中国猪种DRA基因和已报告的NIH小型猪DRA基因结构相同 ,其长度均为 75 9个核苷酸 ,除末端终止密码外 ,编码 2 5 2个氨基酸残基。分析还揭示 ,(1)中国猪种SLA DR基因及其推导的氨基酸序列与人相应基因的同源性明显高于小鼠I E基因 ;(2 )中国猪DR分子 (DRα链和β链 )存在和人CD4分子相结合的HLA同源序列 ,但个别关键氨基酸残基发生改变 ,其改变幅度明显低于小鼠I E分子。人 猪MHC显示较高的同源性 ,在分子水平为人体T细胞同时采用直接和间接方式识别猪SLA这一免疫学现象提供了依据。
In order to explore the role of SLA DR gene structure in pig xenotransplantation, SLA DRcDNA of three Chinese pig breeds was amplified by RT-PCR and then cloned into sequencing vector for bidirectional sequencing to obtain a complete reading frame The three new DRB alleles with different structures and sequences were 801 nucleotides in length, encoding 266 amino acid residues except for the terminal stop codon. The DRA genes of three Chinese breeds and the reported Of the NIH minipig DRA gene structure of the same length, its length is 759 nucleotides, in addition to the terminal stop codon, encodes 2552 amino acid residues. The analysis also revealed that: (1) SLA DR gene and its deduced amino acid sequence of Chinese pig breeds were significantly higher homologous with human corresponding genes than mouse IE genes; (2) DR porcine DR molecules (DRα chain and β chain) And human CD4 molecule HLA homologous sequences, but some key amino acid residues changed, the change was significantly lower than the mouse IE molecules. Human pig MHC shows a high degree of homology, providing molecular evidence that human T cells recognize the immunological phenomenon of pig SLA both directly and indirectly at the molecular level.