Identification of B Cells as a Major Site for Cyprinid Herpesvirus 3 Latency

Abstract

Cyprinid herpesvirus 3 (CyHV-3), commonly known as koi herpesvirus (KHV), is a member of the Alloherpesviridae, and is a recently discovered emerging herpesvirus that is highly pathogenic for koi and common carp. Our previous study demonstrated that CyHV-3 becomes latent in peripheral white blood cells (WBC). In this study, CyHV-3 latency was further investigated in IgM IMPORTANCEThis is the first demonstration that a member of the Alloherpesviridae, cyprinid herpesvirus 3 (CyHV-3), establishes a latent infection in the B cells of its host, Cyprinus carpio. In addition, this is the first report of identification of gene transcription during latency for a member of Herpesvirales outside Herpesviridae. This is also the first report that the hypothetical protein of latent transcript of CyHV-3 contains a consensus sequence with homology to a conserved domain of EBNA-3B from Epstein-Barr virus and ICP4 from herpes simplex virus 1, which are genes important for latency. These strongly suggest that latency is evolutionally conserved across vertebrates.

Cyprinid Herpesvirus 3 Il10 Inhibits Inflammatory Activities of Carp Macrophages and Promotes Proliferation of Igm+ B Cells and Memory T Cells in a Manner Similar to Carp Il10

“…The collective data suggest that cyhv3Il10, similar to mammalian viral IL10s, promotes B cell survival and proliferation, possibly increasing the number of latently infected cells in circulation. Our data would therefore support the observation described in a recent study showing that CyHV-3 establishes latency in Igm + B cells from koi carp (55).…”

Virus genomes and virus-host interactions in aquaculture animals

“…Tissue culture and RT-PCR testing results indicate that herpesviruses may become latent in leukocytes and other tissues following a primary infection, and that they can be reactivated from latency by temperature stress [132]. Recently, B cells have been identified as a major site where CyHV-3 can become latent [133].…”

First Report of Occurrences of Two Cyprinid Herpesvirus 3 Variants, I⁺⁺ II^− and I⁺⁺ II^+Δ, in China

“…Carassius auratus) may increase the difficulty in the detection of CyHV-3 during fish transfer and contribute for the distribution of the virus. (Eide et al, 2011;El-Matbouli and Soliman, 2011;Fabian et al, 2013;Reed et al, 2014). The first outbreak of koi herpesvirus disease in East Asian and Southeast Asian can be traced back to 1998 in Korea (Lee et al, 2012), 2002 in Indonesia (Sunarto et al, 2005) and 2003 in Japan (Sano et al, 2004).…”