Screening And Identification Of Cellular Receptors Of Infectious Bursal Disease Virus

Infectious bursal disease virus(IBDV),targeting bursa B lymphocytes,causes severe immunosuppressive disease in chickens,inducing huge economic losses for poultry industry.To date,the functional receptor for IBDV binding and entry into host cells was not very clear.In this study,host proteins of bursal lymphocytes interacting with VP2 were screened by mass spectrometry.Transmembrane protein chicken CD44(Cluster of Differentiation 44)was chosen for the following study,which was identified to interact with IBDV VP2,the major capsid protein.Overexpression and knockdown experiments showed that chCD44 promotes replication of IBDV.Soluble chCD44 and anti-chCD44 antibody blocked virus binding.Furthermore,the results of receptor reconstitution indicated that chCD44 overexpression conferred viral binding capacity in non-permissive cells.More important,although we found that IBDV could not replicate in the chCD44 overexpressed non-permissive cells,but virus could entry into non-permissive cells by chCD44.Our finding reveals that chCD44 as an important component of IBDV receptor complex,could facilitate both virus binding and entry in target cells,by interacting with IBDV VP2 protein.Our study not only impacts the understanding of IBDV binding and entry process,but also sets the stage for further elucidation of infection mechanism of IBDV.