一株引起病毒性脑炎的柯萨奇B3病毒的生物学特性分析

Biological characteristics of a new Coxsackievirus B3 strain isolated from fecal specimens from a child with encephalitis

目的通过分析分离自病毒性脑炎病人的一株柯萨奇病毒B3株KMA103-09生物学特性,研究其致病机理。方法将KMA103-09病毒分别按一定量接种至KMB17细胞、RD细胞、VERO细胞、Hep-2细胞、Hela细胞及MRC-5细胞进行培养,观察细胞的生长情况,并采用微滴法检测病毒在不同时间、不同细胞中的病毒感染滴度;将一定量KMA103-09病毒注射乳鼠和成鼠脑内,观察病毒的致病性,并检查鼠血清中IL-2、IL-4、IL-6、IFN-r、TNF、IL-17A、IL-10含量。结果该病毒株在6种细胞上皆能适应生长,并产生明显的细胞病变效应。病毒在Hela细胞上生长繁殖最快,42h时细胞全部发生病变,感染性滴度达8.625lgCCID50/ml;在MRC-5细胞上病毒的感染性滴度最低,120h才全部发生病变,感染性滴度为5.50lgCCID50/ml。该病毒对一日龄乳鼠致死并在脑、肺和心脏等组织产生病理改变,实验乳鼠血清IL-6、IL-10、TNF含量分别为4.71pg/ml、21.08pg/ml和36.79pg/ml,与阴性对照组比较差异有统计学意义(P<0.05),其余4种皆无表达。该病毒对成鼠不致病,脑、肺、心脏病理检查无异常。结论 KMA103-09病毒在Hela细胞生长适应性良好,对乳鼠致病而对成鼠不致病。

Objectives To analyze the biological characteristics of a human coxsackievirus B3strain（KMA103-09）isolated from fecal specimens from a child with encephalitis and to investigate its role in causing encephalitis. MethodsThe Coxsackievirus B3strain KMA103-09was propagated in KMB17cells,RD cells,VERO cells,Hep-2cells,Hela cells,and MRC-5cells.Cell growth was observed,and the 50%cell culture infective dose of the KMA103-09strain was detected in the various cell lines at different times after infection.A given amount of KMA103-09was injected intracerebrally in suckling mice and adult mice.The pathogenicity of the virus was observed and levels of serum IL-2,IL-4,IL-6,IFN-r,TNF,IL-17A,and IL-10were detected using a Cytokine Kit. Results The CVB3strain KMA103-09adapted as it grew and it had a significant cytopathic effect on the six cell lines.Hela cells were most susceptible to the KMA103-09strain and had the highest infection titer,8.62lgCCID50/ml,42hours post-infection.MRC-5cells were the least susceptible and had lowest infection titer,5.50lgCCID50/ml,120hours post-infection.The virus infected the one-day-old suckling mice and caused death.Pathological changes were found in the brain,heart,and/or lung tissue.Suckling mice had serum IL-6,IL-10,and TNF levels of 4.71pg/ml,21.08pg/ml,and 36.79pg/ml.There were statistically significant（P0.05）differences in these levels in suckling mice.The other four cytokines were not expressed.However,no pathogenicity was noted in adult mice and pathology of the brain,heart,and/or lung tissue revealed no obvious abnormalities. Conclusion Hela cells are the optimal cell line for growth of the Coxsackievirus B3strain KMA103-09.The KMA103-09strain is pathogenic in suckling mice but not in adult mice.