Prevalence of antibodies to the Hawaii strain of human calicivirus as measured by a recombinant protein based immunoassay.

The evaluation of an enzyme immunoassay using recombinant Hawaii virus-like particles (rHV-LPs) with a panel of sera which had been screened previously for antibodies to Norwalk virus (NV) and Mexico virus (MxV) is described. The assay was also applied to study the epidemiology of Hawaii virus. Adult volunteers challenged with the prototype (genogroup II, human calicivirus) HV developed significant IgG responses (16-32 fold rises) following challenge whereas adults challenged or naturally infected with NV (genogroup I) did not. Lesser antibody responses (4-8 fold rises) were demonstrated in volunteers challenged with Snow Mountain agent (SMA) and patients infected by SRSV 'UK3' and 'UK4' strains, indicating a degree of antigenic relatedness among viruses within genogroup II. Comparison of the seroprevalence of IgG antibodies to rHV, rMxV and rNV in 338 children in London showed that infections with genogroup II viruses are prevalent and occur earlier in life than NV. Many young children had antibodies to MxV but not HV indicating that genogroup II viruses have both conserved and antigenically distinct epitopes. A serological study on 566 Canadians aged between 9 and 79 years showed that the prevalence of antibodies to rHV rose with age from 65-100% and from 53-100% for NV. Measurement of antibody response in a heart transplant patient infected with an MxV-like virus showed significant responses to both rMxV and rHV. Continuous monitoring of the patient over two years showed that antibody levels declined rapidly to prechallenge levels after a year.