Type I interferon responses of common carp strains with different levels of resistance to koi herpesvirus disease during infection with CyHV-3 or SVCV

Abstract

22Highlights 24 1. Differences in mortality rates during SVCV and CyHV-3 infections were recorded in carp 25 strains. 26 2. The higher resistance of the Rop strain was related to lower virus load and replication. 27 3. The magnitude of type I IFN response was not positively correlated with survival. 28 4. CyHV-3 has an ability to limit IFN response induced by sensing viral DNA by cells. 29 30 Abstract 34 Carp from breeding strains with different genetic background present diverse levels of 35 resistance to viral pathogens. Carp strains of Asian origin, currently being treated as Cyprinus 36 rubrofuscus L., especially Amur wild carp (AS), were proven to be more resistant to koi 37 herpesvirus disease (KHVD; caused by cyprinid herpesvirus 3, CyHV-3) than strains originating 38 from Europe and belonging to Cyprinus carpio L., like the Prerov scale carp (PS) or koi carp 39 from a breed in the Czech Republic. We hypothesised that it can be associated with a higher 40 magnitude of type I interferon (IFN) response as a first line of innate defence mechanisms against 41 viral infections. To evaluate this hypothesis, four strains of common carp (AS, Rop, PS and koi) 42were challenged using two viral infection models: Rhabdovirus SVCV (spring viremia of carp 43 virus) and alloherpesvirus CyHV-3. Infection experiments confirmed significant differences in 44 mortality between the analysed carp strains. The infection with SVCV induced a low mortality 45 rate and the most resistant was the Rop strain (no mortalities), whereas the PS strain was the most 46 susceptible (survival rate of 78%). During CyHV-3 infection, Rop and AS strains performed 47 better (survival rates of 78% and 53%, respectively) than PS and koi strains (survival rates of 48 35% and 10%, respectively). The evaluation of virus loads and virus replication showed 49 significant differences between the carp strains, which correlated with the mortality rate. The 50 evaluation of type I IFN responses showed that there were fundamental differences between the 51 virus infection models. While responses to the SVCV were high, the CyHV-3 generally induced 52 low responses. Furthermore, the results demonstrated that the magnitude of type I IFN responses 53 did not correlate with a higher resistance in infected carp. In the case of a CyHV-3 infection, 54 reduced type I IFN responses could be related to the potential ability of the virus to interfere with 55 cellular sensing of foreign nucleic acids. Taken together, the results broaden our understanding of 56 how common carp from different genetic lines interact with various viral pathogens. 57 monitoring the development of the infection in four tissues and subsequently measuring type I 113 IFN responses. Further in vitro studies were performed to better characterise anti-IFN actions of 114 CyHV-3. 115 116 117 For the infection experiments, the carp were transported to the National Veterinary 131Research Institute in Pulawy, Poland at a mean weight of 10.3 ± 8.2 g and placed at 18 °C in a 132 flow through system two week...

Different transcriptional response between susceptible and resistant common carp (Cyprinus carpio) fish hints on the mechanism of CyHV-3 disease resistance

“…Previous transcriptomic studies in susceptible CyHV-3 infected common carp, shared our observation of a wide response that is mainly immune related [36, 37]. More specifically, IFN-mediated response to CyHV-3 infection has been reported recently also for other carp strains with variable survival levels [38]. The IFN response in fish, similarly to mammals, acts as an important part of innate anti-viral immunity [46] and thus, induction of this pathway is not suprising.…”

“…Since the two fish types are considerably different, both genetically and phenotypically [18, 35], it was not surprising to find many transcriptional differences (840 DEGs) at day 0 (S0/R0) driven by basal genetic variation. As reported before, CyHV-3 infects both fish types, mortalities of susceptible fish start around day 8 post-infection and by day 6 post infection, viral loads in susceptible fish are significantly higher than in resistant fish [18, 38]. Thus, day 4 post-infection was chosen here to study the gene expression differences that can potentially explain why resistant fish more effectively control the viral load and survive.…”

Transcriptional Programs Underlying Cold Acclimation of Common Carp (Cyprinus carpio L.)

“…The common carp is characterized with the economic importance and genetic diversity in the genome. The genetic diversity of common carp strains leads to distinct phenotypes in body color, body shape, scale pattern, growth rate, and response and tolerance to pathogens ( Nielsen et al, 2010 ; Odegard et al, 2010 ; Jiang et al, 2014 ; Xu et al, 2014b ; Adamek et al, 2019 ), offers an attractive model to dissect the genetic basis of the economic traits. The genetic background of fish also plays pivotal roles in shaping the transcriptional responses to environmental stresses, which in turn determines the resistance of the animals to the subsequent lethal level challenges of the same stress ( De Nadal et al, 2011 ).…”

Mass mortality associated with koi herpesvirus in common carp in Iraq

“…A single nucleotide polymorphism (SNP) in IL-10a along with elevated expression of IL-12 p35, IFN ɑβ and TLR 9 contributes to this resistance [ 35 ]. This was not the case, however, in a study in which the immune responses in different carp strains with different levels of resistance to KHVD were evaluated: it was found that the resistant Ropsha (Rop) and Amur wild (AS) strains had a higher survival rate than Prerov scale (PS) and koi strains, but the levels of IFN type 1 did not correlate with this resistance phenotype [ 36 ].…”