Dexamethason 및 Polyinosinic– polycytidylic acid 가 Koi herpesvirus 감염에 미치는 영향

Abstract

Carp (Cyprinus carpio) is a globally used fish species worldwide for food and ornamental purposes, with Asia accounting for 75% of total production. Viruses such as cyprinid herpesvirus-3 (carp herpesvirus, KHV), an infection caused by a pathogen contributing to the decline in carp aquaculture production, are transmitted globally through the live animal trade. Herpes viruses have a mechanism to remain latently infected in host cells and reactivate upon external stress, and latent infection can facilitate viral transmission. Similarly, KHV, an alloherpesvirus, can induce a latent infection depending on the host's immune status, but the pathway by which it evades cellular immunity is unknown. Therefore, to explain the latent infection, the infection characteristic of KHV at different immune states in the host could provide one of the important clues. This study aimed to determine genetic characterization for KHV recently isolated from necrotic gills and excessive mucus koi carp in aqua-farm in Korea and KHV infection characteristics in two different host cells’ immune status. The genotype of KHV identified was Asian, and the genetic sub-typing identified as A1, which is predominantly found in Asia. In this study, two immunomodulator agents (dexamethasone, DEX and polyinosinic-polycytidylic acid, Poly I:C) were used to alter the immune status of the host (common carp brain (CCB) cell and carp), and they were infected with KHV by immunomodulator pre-treated respectively. The results showed that NF-κB was down-regulated in CCB cells after DEX treatment, which was different from the results of Poly I:C. Notably, the viral genome copy of KHV after DEX treatment was higher than that of CCB cells infected with KHV alone, indicating that innate immunity affects KHV infection. The results of this study suggest that innate immunity is likely to be an important factor in KHV infection and may be used as a basic study for the characterization of latent infection.