VZV expresses homologues to all of the major glycoproteins of HSV, except gD. We previously identified in VZV a highly conserved DNA coding region for a 19 amino acid (aa) sequence of a major HSV-1 gD epitope. Additional gD coding sequences are not in the published VZV sequence.

Marek's disease virus (MDV), a herpesvirus of chickens, which, like VZV, is strongly cell-associated in tissue culture, has been shown to lose DNA sequences during passage in tissue culture. MDV also contains different antigens in its cell-associated vs. its cell-free form. We hypothesized that wild VZV contains a complete homologue to HSV gD in vivo which is similarly modified during tissue propagation. We compared VZV from vesicle fluid with cell-associated tissue-culture grown VZV for the presence of the conserved coding region for the 19 aa gD sequence and putative HSV gD flanking regions by polymerase chain reaction (PCR).

Vesicle fluid from two patients with varicella was collected and stored in viral transport medium. A portion was used for tissue culture. Primers were designed to flank the 19 aa conserved region and a downstream BglI restriction site. Amplification of each vesicle fluid virus and corresponding cell-associated tissue-cultured virus produced PCR products of the same apparant molecular weight as predicted from the published VZV sequence, indicating that neither vesicle fluid-derived nor tissue-culture propagated VZV contain flanking regions of the highly conserved 19 aa HSV gD sequence. Therefore, VZV does not appear to encode a complete HSV gD homologue.