Characterization of monoclonal antibodies generated against Norwalk virus GII capsid protein expressed in Escherichia coli

The Norwalk virus (NV) causes outbreaks of acute non-bacterial gastroenteri tis in humans. The virus capsid is composed of a single 60 kDa protein. The capsid protein of NV36 (genogroup II, Mexico virus type) was expressed in an Escherichia coli system and ten monoclonal antibodies (MAbs) were genera ted against it. The reactivity of these MAbs was characterized using enzyme -linked immunosorbent assay (ELISA) and Western blot (WB) analysis towards 20 overlapping fragments of the NV36 capsid protein expressed in E. coli, A ll of the MAbs recognized sequential (continuous) epitopes on the three ant igenic regions, Six of the 10 MAbs recognized fragment 2 (equivalent residu es 31-70), three MAbs recognized fragment 13 (residues 361-403) and one MAb recognized fragment 7 (residues 181-220), suggesting that the N-terminal d omain (residues 1-220) may contain more antigenic epitopes than the C-termi nal domain (residues 210-548), Furthermore, two MAbs (1B4 and 1F6) reacted in WE with three purified NV strains (genogroup II) derived from patients' stool samples, It was also found that genogroup I recombinant NV96-908 (gen ogroup I, KY89 type) could be detected as sensitively as recombinant NV36 ( genogroup II) by ELISA with a set of the MAbs produced here.