The ORF50 gene of the varicella-zoster virus (VZV) encodes glycoprotein M which is conserved among all herpesviruses. VZV gM is predicted to be an eight-transmembrane envelope glycoprotein modified with a complex N-linked oligosaccharide. It mainly localizes to the trans-Golgi network, where final virion envelopment occurs. Studies in which VZV gM was disrupted suggest that the gM plays an important role in virus cell-to-cell spread via enhancement of syncytium formation. Our anti – VZV ORF 50 antibody VZ 50C.04 works in ELISA (on immunogen) and each LOT was validated for Western blot (of VZV infected cell lysates) where it specifically recognizes a protein species of ~50 kDa in lysates obtained from VZV infected cells (described in J Virol. 2013 Jun;87(12):6943-54.).