Identification of Putative Vero Cell Protein(s) that Bind Specifically to Recombinant Envelope Protein of Dengue Virus Type 2

Abstract

Purpose : To identify protein targets in host (vero) cell since there is currently no therapy or a licensed tetravalent vaccine to combat all the four virus serotypes of dengue virus. Methods : The domain III of the dengue virus encoded envelope protein was expressed in pET28a expression vector and the purified recombinant protein was labeled with biotin without altering its immunogenicity. Vero cell proteins on nitrocellulose membrane reacted with recombinant envelope protein domain III to identify viral target proteins in vero cells. Results : The 45 KDa, 43 KDa and 30 KDa plasma membrane proteins were identified as viral envelope targets. Competitive binding assay showed these proteins competing with dengue virus binding. MTT assay indicate that viability of vero cells increases in cultures pretreated with 45 KDa, 43 KDa and 30 KDa proteins before dengue infection. Conclusion : These results indicate the possible role of these proteins in viral binding to vero cells. The study provides a preliminary insight that would aid in determining the target epitopes against protein E domain III of dengue virus and hence, formulation of a vaccine for preparing neutralizing antibodies. Keywords : Dengue virus envelope, Biotinylation, Ni-NTA purification, Target epitopes, Plaque assay, Competitive blocking assay