Varicella-zoster virus (VZV) is a highly infectious, human host restricted alphaherpesvirus that causes varicella, establishes latency in sensory ganglion neurons and can reactivate to manifest as zoster. VZV gB, a 931 amino acid (aa) protein encoded by open reading frame (ORF)31, together with the VZV gH-gL heterodimer, trigger cell fusion in vitro, in the absence of other viral proteins.