Viral Escape Assay

The viral escape assay is a cell‑based experimental approach used to evaluate the capacity of replicating viruses to acquire resistance under sustained selective pressure from neutralizing antibodies derived from vaccination, natural infection, or therapeutic administration. The assay is applied as an exploratory tool to investigate viral evolution and antibody‑mediated selective escape rather than as a routine quantitative immunogenicity endpoint. VisMederi has extensive expertise in the evaluation of SARS-CoV-2 escape mutants (SARS-CoV-2 escape from a highly neutralizing COVID-19 convalescent plasma.), with the capability to readily extend this approach to other viral pathogens, including influenza viruses. Our method involves serial passaging of live virus in permissive cell cultures in the presence of either serial dilutions or fixed high concentrations of polyclonal sera or monoclonal antibodies. This selective antibody pressure promotes the emergence of viral variants with reduced susceptibility to antibody-mediated neutralization, enabling the characterization of potential escape mutations. Viral replication is monitored by cytopathic effect and/or infectivity readouts, and breakthrough viruses are isolated and further characterized by neutralization testing and genomic sequencing to identify escape‑associated mutations. This assay provides functional and mechanistic insight into potential immune escape pathways and antigenic stability of vaccine‑induced antibody responses.