Architects of folding, editors of immunity: the strategic use of N-glycans in vaccine design

Abstract

Public health strategies rely heavily on vaccination to reduce the burden of infectiousdiseases. From 1974 to 2024, vaccination is estimated to have prevented 154 milliondeaths and contributed to 40% of the decline in global infant mortality, eradicating oncedevastatingpathogens. The sudden emergence of highly transmissible pathogens can disrupt daily life, increase mortality, and severely affect economic growth, especially in low and middle income countries (LMICs). Several types of vaccines have been developed, with traditional formulations based on attenuated or inactivated pathogens. Subunit vaccines-based on pathogen proteins- offer a safer and versatile alternative when compared to conventional inactivated or attenuated vaccines, minimizing infection risks while eliciting protective immune responses.Achieving robust and broad immunity depends not only on which pathogen regions areselected as antigens but also on how these regions are presented to the immune system.Immunodominant regions are often the most variable in sequence, or structurallyhidden by post-translational modifications that help pathogens evade recognition. Amongthese modifications, protein N-glycosylation plays a central—and often paradoxical—role inantigen biology and recombinant vaccine antigen design. Enveloped viruses such as HIV-1 orinfluenza A bear N-linked glycans in theirmembrane proteins and use the host’s glycosylation toshield important epitopes. Notably, N-glycosylation contributes to both viral immuneevasion and glycoprotein folding and ER quality control, albeit through distinct glycan structures. In patients with congenital disorders of glycosylation such as MOGS-CDG-a disordercaused by mutations in glucosidase I, the first enzyme involved in glycan remodeling aftertransfer to proteins – the replication of many enveloped viruses is reduced. This dual roleof N-glycosylation poses a challenge for vaccine development: producing cost-effective antigenswhile ensuring proper folding and immunogenicity. These underscore the need to conceptuallyseparate the folding and immunogenic functions of N-glycans. Viewing glycans as tunable designelements opens new opportunities for rational, cost-effective, and globally accessible vaccinedevelopment. In this article we dissect the roles of N-glycosylation in rational antigenic design.