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Add To Calendar 27/04/2016 12:00:0027/04/2016 12:20:00America/ChicagoAsian-Pacific Aquaculture 2016   RESEARCH PROGRESS ON THE FIGHT AGAINST GRASS HEMORRHAGIC DISEASE IN CHINA Crystal 4The World Aquaculture Societyjohnc@was.orgfalseanrl65yqlzh3g1q0dme13067DD/MM/YYYY


Liqun  Lu
Key Laboratory of Freshwater Fishery Germplasm Resources, Shanghai Ocean University, 201306 Shanghai, P.R.China

Grass carp reovirus (GCRV), the representative member of aquareovirus-C, serves as a model in studying the pathogenesis of aquareovirus. GCRV is currently one of the most virulent pathogens for grass carp Ctenopharyngon idellus in China, which is one of the most economically important fish species cultivated in China with an annual production of more than 3.6 million metric tons. The frequent outbreaks of hemorrhagic disease due to GCRV infection resulted in significant economic losses in grass carp cultivation business.Vaccination of grass carp with inactivated virions or attenuated live virus is effective in preventing viral hemorrhagic disease in grass carp, but it has many limitations, such as regional variability, high costs, and the fact that it is difficult to administer in an aquatic environment . So far, more than 20 strains of GCRV have been reported, and ten of them have known complete genome sequences. Additionally, Wang et al. reported the co-existence or co-infection of two genetically distant genotypes. Based on current evidence, vaccination strategies against one genotype of GCRV would be not adequate in disease prevention. Thus, there is a clear need to develop effective anti-GCRV drugs, which should be environmentally friendly.  In our study to isolate and characterize the receptor protein used by GCRV to gain entry into Ctenopharyngodon idellus kidney (CIK) cells, the 37-kDa/67-kDa laminin receptor (LamR) was identified as the interacting partner for outer capsid protein VP5 of GCRV through yeast two-hybrid screen in Saccharomyces cerevisiae. LamR located in plasma membrane of CIK cells, and significantly increased levels of LamR correlated with efficient GCRV infection in the cells. Both VOPBA (virus overlay protein binding assay) and Co-IP (co-immunoprecipitation) assays demonstrated that GCRV particles specifically bound to LamR protein. Furthermore, infection of CIK cells with GCRV was inhibited in a dose-dependent manner by either laminin protein or small plant compound epigallocatechin gallate, EGCG. Quantitative analysis further showed that complete inhibition of GCRV infection was achieved by EGCG in a dose of 40 μg/ml, which appeared to be more effective than that of the laminin protein. A key finding of the current work was that a low-molecular plant compound, EGCG, effectively blocked GCRV infection in vitro. These results collectively indicate that LamR acts as the receptor for GCRV on the surface of CIK cells through binding with outer capsid VP5 protein, and plant compound EGCG poses as a promising small molecule drug for grass hemorrhagic disease caused by GCRV infection.

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