Figure.

Anti-Norovirus serum antibody titres in rabbit immunized with Norovirus GII.4 virus-like particles. Log-transformed IgG titre and 50 per cent blocking titre (BT₅₀) in the post-immunization rabbit serum samples, Post 1 to Post 5, obtained at two-week interval after the respective dose, are shown. Each serum dilution was tested in duplicate experiments. The IgG titre was defined as the reciprocal of the highest serum dilution indicating positive reaction while 50 per cent blocking titre was defined as the reciprocal of the highest dilution with ≥50 per cent blocking.