Table 1.

Current models of non-productive VZV infection of human neurons.

Model	Virus inoculum	Results	Reference
fetal neural stem cells implanted into SCID mouse brain	cell-associated	3 weeks p.i., VZV proteins encoded by ORFs 62, 63 & 47 are detected; VZV gE is rarely detected.	[23]
fetal DRG implanted under SCID mouse kidney capsule	cell-associated	8 weeks p.i., no infectious virus is released; VZV DNA copy number is stable with limited VZV transcription (62/63 only).	[24]
embryonic neural stem cell (hNSC)	cell-free	14 days p.i., no CPE or release of infectious virus, although VZV DNA, RNA, and protein are detectable.	[30]
induced pluripotent stem cell	cell-free	14 days p.i., no CPE or release of infectious virus, although VZV DNA, RNA, & proteins are detected; virions seen - mostly aberrant; no markers of activated apoptotic pathway present.	[33,34]
human neural progenitor cells tissue like assemblies	cell-free	first 18 days p.i. show an increase of both VZV DNA and RNA, which plateaus. At 3 months p.i., no CPE is evident and only sporadic release of infectious virus is seen.	[35]