To overcome the disadvantages of being limited by antigen size, conformation and assembly of VLPs when constructing cVLPs using genetic fusion methods. We offer chemical conjugation methods to construct cVLP from VLPs generated from plant platforms. In this strategy, the target antigen and VLPs are first produced separately and subsequently linked together by attaching the antigen to the surface of the VLPs. Antigens can be covalently or non-covalently bonded to VLPs constructed from plant platforms to form cVLPs. The most common covalent method is through the use of heterobifunctional chemical crosslinkers with amine and sulfhydryl reactive arms. For example, cysteine-containing antigens can be embedded to VLPs with amino acid residues on their surface. Non-covalent coupling strategies include the use of streptavidin as a junction to link biotinylated antigens and VLPs through their specificity and strong interactions.

Advantages of Chemical Conjugation

This approach allows for the attachment of antigens of different sizes and types to VLPs, including non-protein antigens, and also allows for the manipulation of the binding sites of antigens to VLPs to maximize exposure of conjugated antigens. This ability is essential for the development of vaccines against pathogens with antigenic versatility, as larger proteins are more effective than shorter peptides at eliciting antibodies and eliciting an immune response.

Common conjugation chemistries. (Rohovie MJ, et al., 2017)