VZV ORF20 (UniProtKB – Q6QCN5) encodes a capsid protein, an orthologue of HSV1 protein UL38. During infection, VZV ORF20 protein localizes to both nuclei and cytoplasm of infected cells and, together with proteins encoded by VZV ORFs 21, 23, 33, 40 and 41, forms the icosahedral nucleocapsid core of VZV virions (Nat. Rev. Microbiol. 12, 197–210 (2014)). Our anti-VZV 20 antibody VZ 20.13 works in ELISA (on immunogen), IF (on VZV infected cells) and each LOT is validated only for Western blot of VZV infected cell lysates, where it recognizes a protein of ~55 kDa, which corresponds well to the predicted protein size of 54 kDa (described in J Virol. 2013 Jun;87(12):6943-54.).