Influence of temperature on the antigenic changes of virus-like particles

PURPOSE: In this study, we investigated whether the antigenic changes of the virus-like particles (VLPs) are affected by the temperature during storage. MATERIALS AND METHODS: After exposing the recombinant influenza VLPs to various temperatures for a period, antigenic changes were examined through in vitro hemagglutination receptor binding assay and in vivo mouse experiments. RESULTS: Influenza VLPs were exposed at three different temperatures of low, middle, and high on a thermo-hygrostat. High temperature exposed influenza VLPs were showed significantly reduced HA activity and immunogenicity after mouse single immunization over time compared low and middle. When the VLPs exposed to the high temperature were inoculated once in the mice, it was found that the immunogenicity was significantly reduced compared to the VLPs exposed to the low temperature. However, these differences were almost neglected when mice were inoculated twice even with VLPs exposed to high temperatures. CONCLUSION: This study suggests that similar protective effects can be expected by controlling the number of vaccination and storage conditions, although the antigenic change in the VLP vaccines occurred when exposed to high temperature.