Application Of Cellular Receptor SLAM/CD 150 For The Detection Of Peste Des Petits Ruminant Virus (PPRV)

Peste des petits ruminant(PPR)is an economically important severe viral disease of small ruminants that affects primarily respiratory and digestive tract.PPR was first reported in Ivory Coast(Cote d’Ivoire)of West Africa in 1942 and now the disease is spreading massively across the globe which has reached to 43 countries and the risk of spreading PPR is still high.Specific detection of PPR virus(PPRV)antigen plays an important role in the disease control and eradication program.In addition,although goat and sheep are the primary hosts of PPR,studies have continuously reported the prevalence of circulating antibodies in large ruminants,which could bring a potential challenge to effectively control and eradicate PPR.In this study,first an indirect enzyme-linked immunosorbent assay based-on recombinant goat SLAM(signaling lymphocyte activation molecule,PPRV cellular receptor)as the capture ligand was successfully developed for the detection of PPRV antigen(PPRV SLAM-iELISA).Then after seroprevalence of PPR antibodies were studied in cattle of Nepal.For the development of indirect ELISA,the extracellular domain of goat SLAM was successfully expressed.Then,the different parameters of ELISA such as coating buffer,blocking buffer,appropriate concentration of SLAM protein were optimized and standardized.The data showed that the assay was highly specific for PPRV with no cross-reactions among foot-and-mouth disease virus,Orf virus,sheep pox and goat pox virus,and a sensitivity with a detection limit of 1.56×101 TCID50/reaction(50μL).Assessment of 136 samples showed that the developed PPRV SLAM-iELISA was well correlated with real-time RT-qPCR assays and commercially available sandwich ELISA for detection of PPRV.The relative sensitivity and specificity of the assay was obtained to be 94.73% and 100.83%,respectively,when compared with RT-qPCR and the sandwich ELISA.These results suggest that the developed PPRV SLAM-iELISA is suitable for specific detection of PPRV antigen.Moreover,this study also investigated the prevalence of PPR antibodies in unusual host in Nepal.In Nepal,seroprevalence of PPRV antibodies in cattle have not been monitored yet.To address this,a total of 255 cattle sera were collected from Rupandehi,Banke,Bara and Chitwan districts of Nepal where outbreak of PPR in small ruminants was reported previously.The sera samples were tested by competitive ELISA and the result indicated the prevalence of 5.88% PPRV antibodies in cattle which indicates the exposure of cattle to PPRV.To make the disease control program effective,intensive monitoring of both domestic and wild animals is very important.This study demonstrated for the first time that the goat SLAM/CD150 can be used for the detection of PPRV slam-iELISA method can be used for the development of diagnostic method for the specific detection of PPRV.