The E. coli derived 20 kDa recombinant protein contains the West-Nile virus N-terminal Pre-M immunodominant region (MVTLSNFQGKVMMTVNATDVTDVITIPTAAGKNLCIVRAMDVGYLCEDTITYECPVLAAGNDPEDIDCWCTKSSVYVRYGRCTKTRHSRRSRRSLTVQTHGESTLANKKGAWLDSTKATRYLVKTESWILRNPGYALE).The protein is fused with 6x His tag at C-terminal.