Distinct polymorphisms in a single herpesvirus gene are capable of enhancing virulence and mediating vaccinal resistance.

ABSTRACT: Modified-live herpesvirus vaccines are widely used in humans and animals, but field strains can emerge that have a higher virulence and break vaccinal protection. Since the introduction of the first vaccine in the 1970s, Marek's disease virus overcame the vaccine barrier by the acquisition of numerous genomic mutations. However, the evolutionary adaptations in the herpesvirus genome responsible for the vaccine breaks have remained elusive. Here, we demonstrate that point mutations in the multifunctional meq gene acquired during evolution can significantly alter virulence. Defined mutations found in highly virulent strains also allowed the virus to overcome innate cellular responses and vaccinal protection. Concomitantly, the adaptations in meq enhanced virus shedding into the environment,

SUBMITTER: Conradie AM 

PROVIDER: S-EPMC7758048 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature