A rabies mRNA vaccine with H270P mutation in its glycoprotein induces strong cellular and humoral immunity.

Rabies is a lethal zoonotic disease that kills approximately 60,000 people each year. As the sole virion-surface protein, the rabies virus glycoprotein (RABV-G) mediates its host-cell entry. RABV-G's pre-fusion conformation displays major known neutralizing antibody epitopes, which can be used as immunogen for prophylaxis. H270P targeted mutation can stabilize RABV-G in the pre-fusion conformation. Herein, we report the development of a highly promising rabies mRNA vaccine composed of H270P targeted mutation packaged in lipid nanoparticle (LNP), named LNP-mRNA-G-H270P. Humoral and cellular immunity of this vaccine were assessed in mice comparing to the unmodified LNP-mRNA-G and a commercially available inactivated vaccine using one-way analysis of variance (ANOVA) followed by Dunnett's multiple comparisons test. The results show the titer of RABV-G-specific IgG and virus-neutralization antibody titers (VNTs) in LNP-mRNA-G-H270P group were significant higher than those in LNP-mRNA-G and inactivated vaccine groups. Likewise, IFN-γ-secreting splenocytes, level of IL-2 in the supernatant of spleen cells, as well as IFN-γ-producing CD4 T cells in LNP-mRNA-G-H270P group were significant higher than those in the other two vaccine groups. Hence, these results demonstrated that targeting the H270P mutation in RABV-G through an mRNA-LNP vaccine platform represents a promising strategy for developing a more efficacious rabies vaccine.