Analysis of Mosquito-Borne Flavivirus Superinfection in Culex tritaeniorhynchus (Diptera: Culicidae) Cells Persistently Infected with Culex Flavivirus (Flaviviridae).
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.
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.
Ryusei
R
Kuwata
Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan. Corresponding author, e-mail: hisawa@nih.go.jp.
Haruhiko
H
Isawa
Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
Keita
K
Hoshino
Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
Toshinori
T
Sasaki
Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
Mutsuo
M
Kobayashi
Laboratory of Veterinary Microbiology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi City, Yamaguchi 753-8511, Japan.
Ken
K
Maeda
Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
Kyoko
K
Sawabe
D000818:Animals; D002460:Cell Line; D003465:Culex / Q000502:physiology*; D005260:Female; D018178:Flaviviridae Infections / Q000635:transmission*; D005416:Flavivirus; D015163:Superinfection
Culex flavivirus; Culex tritaeniorhynchus; Japanese encephalitis virus; dengue virus; superinfection exclusion