Variola virus and vaccinia virus antigens (VARV/VACV antigens)

Variola virus (VARV) and Vaccinia virus (VACV) antigens are a group of viral proteins that serve as the primary targets for medical countermeasures against smallpox and other orthopoxvirus diseases. These antigens include structural components of the two infectious forms of the virus: the mature virion (MV) and the extracellular enveloped virion (EEV). Key antigenic targets such as L1, A27, A33, and B5 are involved in critical stages of the viral life cycle, including host cell attachment, membrane fusion, and efficient cell-to-cell spread (PubMed: 16439522). Therapeutic interventions targeting these antigens include live-attenuated and non-replicating vaccines, which elicit a broad repertoire of neutralizing antibodies, and specific antiviral drugs. For example, tecovirimat (TPOXX) targets the highly conserved VP37 envelope wrapping protein to prevent the formation of EEV, thereby halting the spread of the virus within the host (PubMed: 18322231). Additionally, brincidofovir acts as a prodrug that inhibits the viral DNA polymerase, another essential antigenic and functional target. Monitoring the immune response to these antigens through neutralizing antibody titers is a standard method for evaluating vaccine efficacy and biodefense readiness.

Other names

Orthopoxvirus antigensSmallpox antigensPoxvirus surface proteinsVP37 (F13L)L1 proteinA33 proteinB5 proteinA27 protein

Inhibition of the VP37 envelope wrapping protein to prevent viral egress; inhibition of viral DNA polymerase to block genome replication; antibody-mediated neutralization of viral particles to prevent host cell entry.