Comparison of Microneutralization and Histo-Blood Group Antigen-Blocking Assays for Functional Norovirus Antibody Detection.

The development of an in vitro cultivation system for human noroviruses allows the measurement of neutralizing antibody levels. Serum neutralizing antibody levels were determined using a GII.4/Sydney/2012-like virus in human intestinal enteroids in samples collected before and 4 weeks after administration of an investigational norovirus vaccine and were compared with those measured in histo-blood group antigen (HBGA)-blocking assays. Neutralizing antibody seroresponses were observed in 71% of 24 vaccinated adults, and antibody levels were highly correlated (r = 0.82, P < .001) with those measured by HBGA blocking. HBGA-blocking antibodies are a surrogate for neutralization in human noroviruses. NCT02475278.