Gene expression analysis of common carp (Cyprinus carpio L.) lines during Cyprinid herpesvirus 3 infection yields insights into differential immune responses

Abstract

Cyprinid herpesvirus 3 (CyHV-3), also known as koi herpesvirus (KHV), is the etiological agent of a virulent and lethal disease in common and koi carp. This study aimed to determine the genetic basis underlying the common carp immune response to the CyHV-3 virus. Two common carp lines (R3 and K) were infected with CyHV-3 by immersion. The R3 line presented a 20% higher survival rate compared to the K line and significantly lower viral loads as measured at day 3 post infection (p.i.). Microarray analysis using a common carp slides containing a number of 10,822 60-mer probes, revealed that 581 genes in line K (330 up-regulated, 251 down-regulated) and 107 genes in line R3 (77 up-regulated, 30 down-regulated), showed at least a 2-fold difference in expression at day 3 p.i. compared to day 0. Genes which showed at least a 4-fold difference in expression in both lines were selected as potential markers of a CyHV-3 infection in common carp. Additionally, 76 genes showed at least 2-fold differentially expression between K and R3 lines at day 3 p.i. Significantly higher expression of several immune-related genes including number of those which are involve in pathogen recognition, complement activation, MHC class I-restricted antigen presentation and development of adaptive mucosal immunity was noted in more resistant R3 line. Further real-time PCR based analysis provided evidence for higher activation of CD8(+) T cells in R3 line. This study uncovered wide array of immune-related genes involved into antiviral response of common carp toward CyHV-3. It is also demonstrated that the outcome of this severe disease in large extent could be controlled by genetic factors of the host.

Interaction between type I interferon and Cyprinid herpesvirus 3 in two genetic lines of common carp Cyprinus carpio

“…At 72 hpi, the virus load and the expression levels of the viral gene encoding for CyHV-3 TK were significantly different between the 2 analysed carp lines. Carp from the more resistant line R3 harboured a significantly lower virus load (based on the amount of CyHV-3 specific DNA and thymidine kinase expression) in skin and head kidney than carp from the more susceptible line K. A similar difference was found in the trunk kidney by Rakus et al (2012). It appears that virus spread from the skin to the internal organs and may suggest a systemic character of the infection in both lines, with a more severe disease progression in line K fish.…”

“…As shown by Rakus et al (2012), increased resistance of R3 carp to CyHV-3 could be associated with increased levels of complement activation, MH class I-restricted antigen presentation and activation of CD8 + T cells in R3 carp compared to carp from line K. Most of the differences in gene expression occurred at 24 and 72 hpi. Therefore, these factors were most likely responsible for delaying the replication of the virus and its spread through the more resistant fish.…”

“…CyHV-3 infection was performed as described by Rakus et al (2012). In brief, fish were infected with CyHV-3 by bath immersion for 1 h at 22°C in small plastic containers containing tank water with a virus suspension at an infectivity of 3.2 × 10 2 TCID 50 ml −1 , before being returned to their original tanks.…”

Feeding common carp Cyprinus carpio with β-glucan supplemented diet stimulates C-reactive protein and complement immune acute phase responses following PAMPs injection

“…For example, serum levels of CRP increased up to 6 fold within 40 h of infection with Aeromonas hydrophila [25], and up to 10 fold within 72 h infection with CyHV-3 [personal observation]. In addition, complement activity is also significantly increased in common carp orally stimulated with b-glucan and challenged with Aeromonas salmonicida [17] or challenged with the CyHV3 virus without bglucan stimulation [27]. This study aims to investigate how oral administration of the immunostimulant b-glucan affects the APR in carp induced by LPS and poly(I:C) intraperitoneal injections as mimics of bacterial and viral infections respectively.…”

Activity of the hypothalamus–pituitary–interrenal axis (HPI axis) and immune response in carp lines with different susceptibility to disease

“…They show a low mortality after infection with A. hydrophila (around 40 %) and relatively low parasitaemia after infection with T. borreli (0.19 9 10 7 for R2 and 0.54 9 10 7 for K carp) (Bekh et al 2004;Jurecka et al 2009). In contrast, R3 carp showed higher resistance to cyprinid herpesvirus 3 (CyHV-3) infection than K carp (Rakus et al 2012).…”