Non-intrusive biophysical and immunochemical methods evaluated here for VLP characterization compared with conventional techniques.

*The solution competitive ELISA measures the accessible epitopes on VLPs adsorbed to particulate adjuvant. This method is used to probe the stability samples upon prolonged storage in a more faithful manner as to the intact and accessible epitopes. In addition, this method may also mimic the in vivo antigen presentation to some degree without the needs to dissolve the aluminum adjuvant, which is co-injected with antigen during immunization.