Kuwata Ryusei, Isawa Haruhiko, Hoshino Keita, Sasaki Toshinori, Kobayashi Mutsuo, Maeda Ken, Sawabe Kyoko
Laboratory of Veterinary Microbiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi City, Yamaguchi 753-8511, Japan. Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan. Corresponding author, e-mail:
J Med Entomol. 2015 Mar;52(2):222-9. doi: 10.1093/jme/tju059. Epub 2015 Feb 5.
Superinfection exclusion is generally defined as a phenomenon in which a pre-existing viral infection prevents a secondary viral infection; this has also been observed in infections with mosquito-borne viruses. In this study, we examined the superinfection exclusion of the vertebrate-infecting flaviviruses, Japanese encephalitis virus (JEV) and dengue virus (DENV), by stable and persistent infection with an insect-specific flavivirus, Culex flavivirus (CxFV), in a Culex tritaeniorhynchus Giles cell line (CTR cells). Our experimental system was designed based on the premise that wild Cx. tritaeniorhynchus mosquitoes naturally infected with CxFV are superinfected with JEV by feeding on JEV-infected animals. As a result, we found no evidence of the superinfection exclusion of both JEV and DENV by pre-existing CxFV infection at the cellular level. However, JEV superinfection induced severe cytopathic effects on persistently CxFV-infected CTR cells. These observations imply the possibility that JEV superinfection in CxFV-infected Cx. tritaeniorhynchus mosquitoes has an adverse effect on their fitness.
超感染排除通常被定义为一种现象，即先前存在的病毒感染会阻止二次病毒感染；这种现象在蚊媒病毒感染中也有观察到。在本研究中，我们在三带喙库蚊吉尔斯细胞系（CTR细胞）中，通过用昆虫特异性黄病毒——库蚊黄病毒（CxFV）进行稳定和持续感染，研究了感染脊椎动物的黄病毒——日本脑炎病毒（JEV）和登革病毒（DENV）的超感染排除情况。我们的实验系统是基于这样一个前提设计的，即自然感染CxFV的野生三带喙库蚊通过吸食感染JEV的动物而被JEV超感染。结果，我们在细胞水平上没有发现先前存在的CxFV感染对JEV和DENV进行超感染排除的证据。然而，JEV超感染对持续感染CxFV的CTR细胞诱导了严重的细胞病变效应。这些观察结果意味着，在感染CxFV的三带喙库蚊中JEV超感染可能对它们的适合度产生不利影响。
