TABLE 1.

Identification of alphaherpesvirus virions in axons by TEM or TIEM

Systema	Site of viral particles in axon	Observationsb	Reference
Enveloped virions
HSV—chick embryo DRG	Uncertain	No virions in axons	22
HSV—rabbit optic nerve (retinal ganglia)	Uncertain	Enveloped virions in cisternae (ER); occasional unenveloped capsids	25
HSV—mouse DRG	Proximal	Single enveloped virion; no MTs visible	7
HSV—mouse DRG, celiac ganglion	Proximal uncertain	Periaxonal virions; atypical particles in vesicle-rich region	53
HSV—dissociated rat DRG; in vitro	“Neuritic extension”	Three enveloped virions; no MTs visible	30
PRV—rat CNS sensory vagal processes	Uncertain	Single enveloped virions; no MTs visible	3
HSV—mouse trigeminal ganglion	? Proximal	Several enveloped virions; no MTs visible	26
PRV—sympathetic ganglia	Proximal (and axon hillock)	Many enveloped virions	5, 10
PRV—sympathetic ganglia	Midaxon	Two enveloped virions	5
Unenveloped virions
HSV—DRG, two-chamber system	Mid-distal	Capsids surrounded by MTs	44
HSV—DRG two-chamber system	Mid-distal	Capsids surrounded by MTs; VP5-VP16 colocalization on particles, but not with gB by TIEM	23
HSV—dissociated rat DRG; in vitro	Uncertain	VP5-labeled capsid in axon by TIEM	35
HSV—dissociated DRG	Uncertain	Capsid labeled for VP16 in axon	36
HSV—mouse trigeminal ganglion	Midaxon	U/E capsids identified by TIEM and adjacent to MTs	43
PRV—sympathetic ganglia	Proximal	Two U/E capsids after BFA inhibition	10
HSV—mouse retinal ganglia	Midaxon	Unenveloped capsids (VP5 immunolabeled) (?) enveloped virions	27
Both enveloped and unenveloped virions
HSV—suckling mice, spinal cord	Uncertain	Single U/E capsid in unmyelinated axon; cluster of enveloped virions in cisternae (ER) (myelinated axon)	21
PRV—mouse DRG	Proximal	Several enveloped virions in vesicle-rich region	16
PRV—sciatic nerve	Midaxon	Enveloped and unenveloped virions (not shown)
HSV—DRG in vitro	Mid-distal axon, growth cones, varicosities	Enveloped and U/E capsids in varicosities and growth cones (and adjacent axon)	This study

^aCNS, central nervous system.

^bU/E, unenveloped; MT, microtubule; ER, endoplasmic reticulum; BFA, brefeldin A.