Validation of a serum neutralization test for detection of antibodies specific to cyprinid herpesvirus 3 in infected common and koi carp (Cyprinus carpio)

Abstract

Cyprinid herpesvirus 3 (CyHV-3) is the aetiological agent of a serious infective, notifiable disease affecting common carp and varieties. In survivors, infection is generally characterized by a subclinical latency phase with restricted viral replication. The CyHV-3 genome is difficult to detect in such carrier fish that represent a potential source of dissemination if viral reactivation occurs. In this study, the analytical and diagnostic performance of an alternative serum neutralization (SN) method based on the detection of CyHV-3-specific antibodies was assessed using 151 serum or plasma samples from healthy and naturally or experimentally CyHV-3-infected carp. French CyHV-3 isolate 07/108b was neutralized efficiently by sera from carp infected with European, American and Taiwanese CyHV-3 isolates, but no neutralization was observed using sera specific to other aquatic herpesviruses. Diagnostic sensitivity, diagnostic specificity and repeatability of 95.9%, 99.0% and 99.3%, respectively, were obtained, as well as a compliance rate of 89.9% in reproducibility testing. Neutralizing antibodies were steadily detected in infected carp subjected to restrictive or permissive temperature variations over more than 25 months post-infection. The results suggest that this non-lethal diagnostic test could be used in the future to improve the epidemiological surveillance and control of CyHV-3 disease.

Effect of temperature on the protective efficacy of a live attenuated vaccine against herpesviral haematopoietic necrosis in goldfish

“…The ELISA antibody titre exhibited higher seropositivity rates in the 20-30°C temperature groups compared with the 15°C group. For CyHV-3 (known as koi herpesvirus) infection in carp at a higher water temperature, the antibody response exhibited a positive relationship between water temperature and intensity of the humoral response, when the rearing temperature was adjusted to 14, 24, and 31°C after the vaccination period with a live attenuated vaccine (Cabon et al, 2017;Perelberg et al, 2008). The virus non-permissive temperature of CyHV-2 was identified as 34°C at the high-temperature side F I G U R E 3 Protective efficacy of the P7-P8 vaccine at vaccination temperatures of 15, 20, 25, and 30°C after virulent CyHV-2 challenge.…”

Don’t Let It Get Under Your Skin! – Vaccination Protects the Skin Barrier of Common Carp From Disruption Caused by Cyprinid Herpesvirus 3

“…Immediately after collection, blood samples were centrifuged at 600 × g at 4°C for 15 min, the supernatant serum was collected and instantly frozen at -80°C. The serum neutralisation test (SNT) was performed as described earlier (22) with minor modifications. Briefly: each serum sample was divided into three 10 μL aliquots and heat inactivated at 45°C for 30 min in an Eppendorf 5331 Mastercycler Gradient thermocycler.…”

Elucidation of putative binding partners for the protein encoded by ORF149 of cyprinid herpesvirus 3 in goldfish (Carassius auratus)

“…A recent study by Torrent et al (2016) has demonstrated that the IgMs of asymptotic CyHV‐3 surviving carp recognize an epitope derived from the amino‐terminal of the glycoprotein coded by the ORF149 of CyHV‐3 (Orf149). Monoclonal antibodies (mAbs) were generated by immunizing mice with purified CyHV‐3 particles (Cabon et al, 2017), and these mAbs were used to detect the virus in common carp brain cells by enzyme‐linked immunosorbent assay (Bergmann et al, 2017).…”