Figure 4.
GII.17.2015 is antigenically distinct from earlier GII.17 strains at blockade antibody (Ab) epitopes. Balb/c mice were immunized intramuscularly with 0.2 µg of a single GII.17 virus-like particle (VLP) adjuvanted with monophosphoryl lipid A and alhydrogel and sera were evaluated for blockade Ab titer to VLPs from clusters I (1978), II (2005), and IIIb (2015). Bars denote geometric mean titers, and whiskers denote 95% confidence intervals. Dashed line equals the limit of detection. *Significantly different from homotypic serum (by analysis of variance). EC50, half-maximum inhibitory concentration.