Impact of heating or sonication on VLP immunogenicity. a Schematic depicting vaccination schedule. b C57BL/6 mice were vaccinated two times, with 3 weeks between vaccinations. VLP were untreated, heated at 37°C for 96 h, heated at 75°C for 15 min, or sonicated. Mice were challenged 4 weeks after the final vaccination and the percent survival is shown. p-values determined using Fisher’s exact test to compare survival of each treatment group at the given dose level to control VLP (“untreated”). c Anti-glycoprotein antibody titers of vaccinated mice measured from serum collected 2 weeks after the final vaccination. VLP dose level (10 or 2.5 µg) and treatment (untreated, heating conditions, and sonication status) are indicated on the x-axis. P values determined using one-tailed Student’s t test where *p < 0.05, **p < 0.005, ***p < 0.0005.