CHIKV VLP vaccination and CHIKV challenge.

<p>A) At least 6 weeks old mice were vaccinated with 0.1 µg VLPs, 1 µg VLPs and 1 µg VLPs adjuvanted with Quil A (QA). PBS and GFP were used as a negative control and inactivated CHIKV virus as a positive control (n = 6 per group). Mice were challenged with the Rèunion Island isolate 5 w post infection. Viraemia levels were determined over 6 days. B) Foot size in mm² (width×height) was determined over 16 days post challenge. Statistical analysis shows that mice vaccinated with inactivated CHIKV virus, 1 µg VLPs and 1 µg VLPs adjuvanted with Quil A display significant lack of viraemia or lack of footswelling at times of peak viraemia (1–3 dpi) and peak foot swelling (6–8 dpi) in the control groups, respectively.