Human respiratory syncytial virus (RSV) poses a significant human health threat, particularly to infants and the elderly. While efficacious vaccines based on the F protein have recently received market authorization, uncertainties remain regarding the future need for vaccine updates to counteract potential viral drift. The attachment protein G has long been ignored as a vaccine target due to perceived non-essentiality and ineffective neutralization on immortalized cells. Here, we show strong G-based neutralization in fully differentiated human airway epithelial cell (hAEC) cultures that is comparable to F-based neutralization. Next, we designed an RSV vaccine component based on the central conserved domain (CCD) of G fused to self-assembling lumazine synthase (LS) nanoparticles from the thermophile Aquifex aeolicus as a multivalent antigen presentation scaffold. These nanoparticles, characterized by high particle expression and assembly through the introduction of N-linked glycans, showed exceptional thermal and storage stability and elicited potent RSV neutralizing antibodies in a mouse model. In conclusion, our results emphasize the pivotal role of RSV G in the viral lifecycle and culminate in a promising next-generation RSV vaccine candidate characterized by excellent manufacturability and immunogenic properties. This candidate could function independently or synergistically with current F-based vaccines.
Keywords: RSV; attachment protein G; lumazine synthase; nanoparticle; vaccine.