Molecular characterization of Ebola virus glycoprotein V75A substitution in the 2018-2020 epidemic.

The 2018-2020 Ebola virus disease (EVD) epidemic facilitated the emergence of viral mutations, enhancing the potential for host adaptation during sustained human transmission. Here, we identified the Ebola virus (EBOV) glycoprotein V75A (GP-V75A) substitution as a dominant variant during the epidemic. This substitution, located within the receptor-binding domain, emerged early in the outbreak and rapidly reached high prevalence. GP-V75A demonstrated enhanced infectivity in multiple cell lines and murine models. Mechanistically, GP-V75A increased viral GP binding affinity to the host receptor Niemann-Pick C1 (NPC1) and reduced the dependency on endosomal cysteine proteases for entry. Notably, GP-V75A also significantly reduced the efficacy of NPC1-targeting compounds and neutralizing antibodies. Epidemiological analysis indicated that the rise in GP-V75A prevalence coincided with the increase in case number during the outbreak. These findings provide crucial insights into the evolutionary adaptation of EBOV during large-scale outbreaks and underscore the importance of real-time genomic surveillance for improving epidemic preparedness.