A rapid and simple screening method to identify conditions for enhanced stability of modular vaccine candidates

Virus-like particles (VLPs) and capsomere subunits have been developed as safe and effective vaccine candidates in the fight against infectious diseases. These bioengineered structures are suitable platforms for repetitive high density presentation of foreign epitope modules. However, due to the module's diverse physicochemical properties, modularisation of capsomeres and VLPs requires tailoring of the physicochemical environment specific to each module to maintain protein stability against aggregation. Here, we report a high-throughput technique for screening buffer components to stabilize capsomeres, based on light scattering analysis. This screening method was applied to modular capsomeres presenting peptide epitopes from the rotavirus spike protein VP8 subunit domain, engineered as a next-generation rotavirus vaccine candidate. Among various additives tested, non-ionic detergents, such as Triton X-100, Tween-80 and Tween-20, were able to stabilize modular capsomeres, either alone or in combination with l-arginine, as confirmed with high-resolution size exclusion chromatography. Results demonstrate that tailoring the nature of the environment surrounding self-assembling proteins using small organic molecules can enhance the bioprocessing of modular vaccine capsomeres. The developed screening method potentially provides a powerful approach for rapid tailoring of processing conditions specific to antigenic modules displayed on next-generation recombinant capsomere and VLP vaccines, for low-cost vaccine delivery at global scale.