不同途径感染小鼠诺如病毒对小鼠抗体水平和病毒复制的影响

Serological and Viral Replication of Murine Norovirus in ICR Mice with Different Routes of Artificial Infection

目的探讨小鼠诺如病毒(MNV)不同接种途径对小鼠血清抗体水平和病毒复制的影响。方法 MNV(4×104拷贝/μL)分别以静脉、腹腔联合注射(iv+ip)、饮水(dw)、灌胃(ig)3种不同途径接种ICR小鼠,各组于感染前(0 d)、感染后3 d、6 d、14 d、25 d、34 d、51 d随机剖检2~3只小鼠,收集血清和心、肝、脾、肺、肾、脑、胃肠内容物,利用酶联免疫吸附法(ELISA)和实时定光定量(q RT-PCR)方法分别检测血清抗体和病毒载量。结果所有感染小鼠均无明显临床症状。3种途径接种的小鼠在感染后25 d均可检测到特异性抗体。抗体产生初期以ig接种组抗体水平最高,随后iv+ip接种组抗体水平上升幅度最大并在51 d高于其它接种组。小鼠接种MNV 3 d可在3组接种鼠的胃肠道、脾、脑中检测到病毒核酸,各组的组织脏器病毒载量有差异,其中iv+ip接种组盲肠内容物(3~51 d)、脾(6 d)和肝(14 d)病毒载量高于其它两组。结论不同接种途径对MNV在小鼠抗体水平和病毒载量影响较大。iv+ip感染效果较好,可作为MNV病毒感染模型的有效接种方式。血清抗体ELISA检测结合盲肠内容物核酸检测有利于MNV早期监测。

Objective To investigate the serum antibody levels and viral replication of murine norovirus（MNV）in mice by artificial infecting in a variety of ways. Method ICR mice were inoculated with MNV（4 × 104 copies/μL） respectively through intravenous combining with intraperitoneally（iv＋ip group）, drinking water（dw group）, intragastrical injection（ig group）. Heart, liver, spleen, lung, kidney,brain, gastrointestinal contents samples and serum were taken on 0, 3, 6, 14, 25, 34, 51 day postinfection（dpi）（2～3 mice each time）. q RT-PCR and ELISA method were applied to detect virus RNA and serum antibody. Results Asymptomatic infection has been identified in all mice. The specific antibody can be first detected 25 dpi in three groups. The level of antibodies was the highest in the ig group in early times,then antibody levels of the iv＋ip group rose faster 51 dpi than the other groups. MNV RNA can be detected 3 dpi in the gastrointestinal tract, spleen and brain. Different viral load in each organization among groups. The viral load of cecum contents（3～ 51 d）, spleen（6 d） and liver（14 d） viral load in the iv＋ip group is higher than the other two groups. Conclusion The effects of different inoculation methods on the antibody level and virus replication of MNV were significant. The effect of infection combined intravenous with intraperitoneally come out to be good, which can be used as MNV effective inoculation for animal model. Serum antibody ELISA detection combined with cecum contents nucleic acid detection is advantageous to the MNV early monitoring.