一株狂犬病病毒减毒株CTN-181的表型特性研究

Phenotypic characterization of an attenuated rabies virus strain CTN-181

目的全面了解狂犬病病毒减毒株CTN-181的表型特征,并与其亲本株CTN-1进行比较。方法将CTN-181株病毒在BHK21细胞中培养,观察其细胞病变和空斑形成特性;用细胞培养的病毒以脑内、肌内和口腔的方式接种不同周龄的小白鼠,同时脑内接种家兔和豚鼠,以同法接种其亲本株CTN-1进行毒力比较。另外,将病毒在BHK21细胞连续传10代,在乳鼠脑内传3代观察其弱毒特性的稳定性。结果 CTN-181株在BHK21细胞上培养出现较CTN-1株明显的细胞病变、较高的空斑滴度。CTN-181株对家兔、豚鼠脑内接种不致病,对4周龄以上的小鼠任何途径接种均不致病,而其亲本株CTN-1株对这些动物均致病或致死。CTN-181株通过细胞传10代和乳鼠脑内传3代后减弱的毒力未回升,无弱毒返祖现象。结论 CTN-181是一株减弱且稳定的减毒株,其弱毒的表型特征与WHO推荐用于制备动物和犬的口服疫苗株SAG2相似。

Objective To understand the phenotypic characteristics of an attenuated rabies virus strain CTN-181.Methods Rabies virus strain CTN-181 and its parental strain CTN-1 were compared in parallel in this study.Viruses were grown in the BHK21 cell culture to observe the cytophagenic effect（CPE） and plague formation.At the same time,both stains of virus were inoculated to mice of different ages by three different routes（intracerebral,intramuscular and oral inoculation）.Rabbits and guinea pigs were inoculated intracerebrally to evaluate the virulence of the virus.The CTN-181 strain was serially passed 10 passages in BHK21 cell culture and 3 passages in suckling mice brain to test its virulent reversal effects.Results Comparing to its parental strain CTN-1,the CTN-181 strain induced more apparent CPE and higher PFU titers in BHK21 cell culture.There was no death observed in ic-inoculated rabbits and guinea pigs,and in ic-,im-or oral-inoculated mice of more than 4-weeks old.In contrast,the parental strain CTN-1 caused significant higher death rate in ic-inoculated mice and also induced death or diseases in virus-inoculated rabbits and guinea pigs.The attenuated phenotype of the CTN-181 strain was stable after 10 passages in cell culture or 3 passages in ic-inoculate suckling mice.Conclusions The rabies virus CTN-181 is an attenuated and genetically stable virus strain.Its attenuated phenotypic features are comparable to that of another attenuated strain SAG2 which has been recommended by WHO for the production of live vaccines for using in wild animals and dogs through oral administration.CTN-181 strain provided a new promising candidate for the making of live,oral vaccine in the control of rabies.