Expression and self-assembly of Grimsby virus: Antigenic distinction from Norwalk and Mexico viruses

A cDNA obtained from Grimsby virus (GRV), a Norwalk-like virus, purified fr om a stool sample of a symptomatic adult associated with a gastroenteritis outbreak in the United Kingdom, was used to obtain the complete nucleotide sequence of the second open reading frame (ORF2), The ORF2 sequence of GRV predicts a capsid of 539 amino acids (aa) which exhibits aa identities of 9 6% to Lordsdale virus, 67% to Mexico virus (MXV), and 43% to Norwalk virus (NV). The GRV capsid protein was expressed in insects cells by using a reco mbinant baculovirus, and the resulting virus-like particles (VLPs) possesse d a protein with an apparent molecular weight of 58,000. Hyperimmune antise ra raised against purified GRV, MXV, and NV VLPs were tested in an indirect enzyme-linked immunosorbent assay (ELISA) against GRV, NV, and MXV VLPs, r evealing that GRV is antigenically distinct, from both NV and MXV. The anti genic specificity of the GRV-hyperimmune antiserum was confirmed in an anti gen capture ELISA using GRV-, NV-, or MXV-containing fecal specimens. The e xpression of the GRV capsid protein has, for the first time, allowed the an tigenic comparison of three distinct recombinant Norwalk-like viruses.