Nanoparticle vaccines comprising the respiratory syncytial virus G Protein CX3C chemokine motif induce robust immunity protecting from challenge and disease (P4513)

Abstract BALB/c mice immunized with nanoparticle vaccines comprising RSV G protein CX3C polypeptides in absence of adjuvant had a neutralizing antibody response associated with reduced lung titers following RSV challenge. These mice also had an increased level of RSV G protein-specific IL-4 and IFNγ secreting cells in the lung, and an increased level of RSV M2-specific IL-4 and IFNγ CD8 T cells. There was a significant increase in M2-specific CD8 T cells that trafficked to the lung following RSV challenge despite the mice being vaccinated with a G protein epitope. Pulmonary cell analysis revealed no significant increase in neutrophils (Ly6Ghi Ly6Cint CD125loSiglecF-) or eosinophils (Ly6Gint Ly6Chi CD125hi SiglecF+) in vaccinated mice before or after RSV challenge. The results show that RSV G protein nanoparticle vaccination is safe and effective, induces a neutralizing protective antibody response, increased RSV G protein- and M2-specific T cell responses, and is not associated with pulmonary disease pathogenesis.