FIG. 5.

Mouse antisera blockade of H type 1:NV VLP binding. Groups of four mice were experimentally vaccinated with two doses of either subcutaneously inoculated VRP-NV1 or orally inoculated NV VLPs. VRPs were administered at 10⁷ infectious units via footpad injection, and 200 μg of sucrose-purified NV VLPs was administered by oral gavage by using methods previously described (9). Baseline and day 35 (12 days postboost) antisera were serially diluted and preincubated in NV VLP coated microwells, followed by addition of synthetic, biotinylated H type 1. H type 1 binding was measured as described in the legend to Fig. 4 and in the text. Dashed lines represent 100% H type 1 binding (no preincubated serum). (A) Mean ODs from wells preincubated with the various serum concentrations from four mice inoculated with VRP-NV1. Error bars represent standard deviation. Note that data for preimmune sera from only three of the four VRP-NV1-vaccinated mice is shown because of insufficient sample volume from one mouse. (B) OD values from microwells preincubated with serially diluted sera from one mouse that responded to the orally inoculated NV VLPs. The three other mice did not respond to the experimental vaccination (9). Note the x-axis scale differences in panels A and B.