| With the rapid development of pet industry,the health of pet cats has become a growing concern.Feline panleukopenia caused by Feline panleukopenia virus(FPV)has become one of the most common and serious infectious diseases in cats due to its high infectious and lethal rate.Vaccination is the most effective measure to prevent this disease.At present,the FPV vaccine used in China is mainly imported,which is not only expensive but also cannot meet the increasing demand in China,which has a great impact on the development of our pet economy and wildlife health.Therefore,it is urgent to find out information about the prevalent strains of FPV in our national felis catus and to develop a safe and efficient vaccine on our own.In this study,40 fecal swabs from felis catus diagnosed as positive for FPV by vet hospitals were isolated and identified by cell culture,PCR and transmission electron microscopy techniques,while the proliferation level and pathogenicity of the isolate in infected cats was analysed by establishing a q PCR assay.The results showed that one FPV strain was successfully isolated,which produced typical cytopathia effect on CRFK cells,and that this FPV VP2 sequence was most closely related to the 2018 Chengdu isolate MG764510.1,with 99.2% and 99.3% nucleotide homology to vaccine strains EU498680.1 and EU498681.1,respectively.Animal infection experiments showed that cats in both the experimental and exposed groups showed significant watery diarrhoea and a significant increase in viral load in peripheral blood.Meanwhile,through the construction and prokaryotic expression of recombinant plasmids,this study also explored the effects of small ubiquitin-related modifier(SUMO)pro-soluble tags and molecular chaperones(p KJE8,p KJE7,p Gro7 and p Tf16)on the soluble expression of VP2 protein in the isolate.The results showed that the p ET-28a-VP2,p ET-28a-SUMO-VP2 and p ET-22a-SUMO-VP2 recombinant plasmids expressed predominantly inclusion bodies in the prokaryotic expression system,but the p ET-28a-SUMO-VP2 plasmid significantly increased the soluble expression of VP2 protein when co-expressed with different molecular chaperones.This study provides a new theoretical basis for the subsequent development of FPV subunit vaccines. |
