Study on the propagation of Herpes simplex virus (type 2) into the brain after intraocular injection

Abstract

Herpes simplex virus (type 2) was injected into the left eye of 6-week-old New Zealand albino rabbits. At varying time intervals thereafter samples were taken from the optic system for light and electron microscopic examination. Virus particles were found within the perikaryon of retinal ganglion cells and their axons, as well as within glia, 2 days after the inoculation. On the following day infected neurons and glial cells were found also in the contralateral, but not ipsilateral superior colliculus (SC) and lateral geniculate body (LGB). Since the optic nerve fibers are almost completely decussated in the chiasm, the findings is consistent with an intra-axonal spread of the virus in an anterograde direction from the perikarya of the retinal ganglion cells to the SC and LGB. The present experiment indicates also that while long distances within the nervous system are spanned by viruses by means of the axonal transport mechanism, simultaneously cell-to-cell infection takes place as well. Ultrastructurally, virus particles were found in the axons, located within vesicular or cisternal structures, which probably represent agranular endoplasmic reticulum. A possible role of the axonal endoplasmic reticulum for the transport of virus particles is pointed out.