FIG. 7.

Ultrastructural examination of viral particles in human DRG axons infected with HSV-1. Coverslips with explanted DRG cultures in situ were infected with the clinical isolate CW1 of HSV-1, fixed, and processed for TEM. Areas containing mid- and distal regions of axons were sectioned and examined. (A) Enveloped (arrow) and unenveloped (arrowhead) capsids in growth cones. (B) Partially enveloped capsid (arrowhead) in a growth cone. The inset shows an enlargement of the partially enveloped capsid. A dense, thickened membrane on the vesicle surrounding the viral particle is visible and probably represents tegument and envelope proteins. (C) Enveloped capsids in vesicles (arrows) in a growth cone. (D) Enveloped (arrows) and unenveloped (arrowheads) capsids in an axonal varicosity at an axonal bifurcation. Note the homogeneous size and morphology of unenveloped capsids, equivalent to those within the enveloped virions. Bars, 200 nm.