Figure 1: NoV GII-4-specific serum antibody responses in BALB/c mice. Mice (10 mice/group) were immunized twice (at day 0 and day 21) with a NoV vaccine candidate containing 10 μg GII-4 VLPs. (A) Termination sera of intramuscularly (IM) immunized mice was assayed for NoV GII-4-specific IgG with two-fold dilutions starting at 1:200. Shown are individual titration curves of each immune sera and titration curve of pooled control mice sera (6 mice/group) immunized with the carrier (PBS) only (dashed line). (B) GII-4-specific IgG titration curves of intranasally (IN) immunized mice and pooled control mice sera. (C) Avidity of GII-4-specific IgG antibodies of each immunized mouse was analyzed in modified ELISA assay at a dilution of 1:200 as described in the Materials and Methods. Shown is avidity index ((OD with urea/OD without urea) x 100) of each mouse sera and the mean of the group. Dashed line indicates the cut-off for high avidity antibodies (>50%). (D) GII-4-specific serum IgA titers were assayed with two-fold dilutions (starting at a 1:20) of group wise pooled serum. Shown are mean OD values of the IM, IN and corresponding control mouse groups with the standard errors of the mean (SEM) of the replicates.