摘要
为了解狂犬病病毒口服疫苗株SRV9的基因序列与生物学特性的关系,明确其作为疫苗株的分子基础,通过反转录聚合酶链式反应(RT-PCR),获得了贯穿全基因组的3个重叠的cDNA片段。将获得的cDNA片段分别克隆至pMD-18T载体上并进行序列测定,对测序结果进行拼接得到全长cDNA序列(GenBank登录号:AF499686)。SRV9株与亲本株SADB19全序列比较分析显示,二者同源性为99.8%,SRV9的变异主要发生在糖蛋白的编码区域,共有5个碱基发生改变,在转录酶蛋白编码区出现2个碱基的改变,其他蛋白编码基因均未出现突变;氨基酸比较分析显示,在转录酶蛋白氨基酸序列发生2个改变;糖蛋白成熟肽的第34位、292位、333位和338位氨基酸分别发生了Gly→Glu,Ala→Thr,Arg→Ser,Ile→Val的改变,其中第34位氨基酸位于第抗原区,第333位和338位氨基酸位于第抗原区。这些抗原位点的突变可能是引起病毒蚀斑特性改变、毒力降低和免疫原性及安全性提高的重要原因。
In order to obtain a more complete understanding of oral rabies vaccine candidate strain SRV_9, three cDNA fragments covering the complete genome were obtained by RT-PCR,they were cloned into pMD-18T vector separately and sequenced, the full-length cDNA of Rabies Virus Oral Vaccine Strain SRV_9 was determined(GenBank(Accession No AF499686).The glycoprotein of SRV_9 was compared both with its ancestor SAD B19 and other strains: 3aG,ERA,CVS,etc. The results indicated that there were three amino acid differences in the antigenic site between the vaccine strain SRV_9 and other virus, the 34rd amino acid in antigenic site Ⅱfrom Gly to Glu, the 333rd amino acid in antigenic site Ⅲ from Arg to Ser, the 338rd amino acid in antigenic site Ⅲ from Ile to Val. These mutations may contribute to the attenuation of the virulence and its stability.The sequence analysis would aid in understanding the mechanism of the vaccine?
出处
《中国兽医学报》
CAS
CSCD
北大核心
2005年第4期368-370,共3页
Chinese Journal of Veterinary Science
基金
军队杰出中青年医药卫生科研基金项目(04J016)
