Expression of recombinant Norwalk-like virus capsid proteins using a bacterial system and the development of its immunologic detection

The capsid protein of Norwalk-like virus (NLV) isolates NLV-36 (Mexico viru s type, genogroup II [GII]), NLV-21 (Lordsdale virus type, GII), NLV-114 (u ntyped GII virus), and NLV-96-908 (KY89 virus type, GI) have been expressed in an Escherichia coli system. The expressed recombinant: NLV capsid prote ins, fused with maltose binding protein (MBP-rV) and thioredoxin (TRX-rV) i n E. coli lysate, were analyzed using sodium dodecyl sulfate-polyacrylamide gel eletrophoresis. Rabbit IgG (R-IgG) in hyperimmune serum has been raise d against MBP-rV-36 capsid protein and was purified before further study. D etection of TRX-rVs using an enzyme-linked immunosorbent assay (ELISA) show ed that R-IgG had immunologic reactivity to GII as well as to the GI rV cap sid proteins TRX-rV-36, TRX-rV-21, TRX-rV-114, and TRX-rV-96-908. Results o f Western immunoblot (WB) analysis showed the same broad recognition of R-I gG when using the same samples. The results of the ELISA rests on serum sam ples obtained from patients involved in confirmed outbreaks of NLV proved t hat expressed NLV capsid proteins in E. coli can be detected by NLV-infecte d human serum. In addition, purified NLVs (LD virus types) derived from pat ients' stool could be detected using anti-NLV R-IgG, whereas normal R-IgG d id not react when using WE. Our results strongly suggest that the immunolog ic detection of NLV antigens using anti-rV R-IgG is possible and seems a si gnificant step toward simplification of an NLV detection test. J. Med. Viro l. 60:475-481, 2000. (C) 2000 Wiley-Liss, Inc.