THE ENTRY AND DISTRIBUTION OF HERPES VIRUS AND COLLOIDAL GOLD IN HELA CELLS AFTER CONTACT IN SUSPENSION

Abstract

The way in which herpes virus of a well adapted strain penetrates susceptible HeLa cells has been investigated using thin sectioning techniques for electron microscopy. Mature virus particles and cells were mixed together in suspension cultures for 15, 30, 60, or 120 minutes so that the stages in virus uptake could be followed in sequence. The ingestion of particles of colloidal gold by HeLa cells under similar conditions was studied for comparison in parallel experiments. After 15 minutes' contact, the mature virus was found adsorbed on the surface of the cells but separated from them by a narrow gap in which phosphotungstic acid staining was sometimes able to reveal an extraneous coat which appeared as an amorphous layer on the outer aspect of the plasma membrane. When mixing continued for longer the particles were present in deep invaginations or actual cytoplasmic vacuoles, with their outer layers in various stages of stripping and digestion. The stripped, naked, central portion of the virus was occasionally found in these vacuoles but was more commonly free in the cytoplasmic matrix; the mode of transition between these sites could not be determined. Where contact continued for 2 hours these phenomena were much less frequently observed. The larger particles of colloidal gold were ingested in the same way as the virus, but smaller ones were taken up in micropinocytosis vesicles. The gold passed through membrane-bounded cytoplasmic spaces to accumulate in vacuoles from which, in contrast to herpes particles, it did not escape. These findings are discussed, and considered with particular reference to their bearing on the initiation of infection, the uptake and disposal of particles by cells, and the influence on the latter of virus morphology.

Mild Acidic pH Inhibition of the Major Pathway of Herpes Simplex Virus Entry into HEp-2 Cells

“…HSV penetration into the target cell has been observed by both fusion at the surface of the cell (Morgan et al, 1968 ;Smith & deHarven, 1974;Epstein et al, 1964) and endocytosis (Hummeler et al, 1969;Smith & deHarven, 1974;Dales & Silverberg, 1969). However, several studies have suggested that plasma membrane fusion is the preferred mode of entry for HSV.…”

Growth and Characterization of the Virus of Bovine Malignant Catarrhal Fever in East Africa

“…Recent work with herpes simplex virus, in which electron-opaque tracers were mixed with the virus inoculum, showed clearly that in cell cultures the virus did indeed enter cells as a consequence of phagocytosis and became incorporated into cytoplasmic vesicles (Holmes & Watson, 1963;Epstein, Hummeler & Berkaloff, 1964). The subsequent fate of ingested particles, in the ' eclipse phase ', preceding appearance of newly synthesized virus particles,…”

Roles for Endocytosis and Low pH in Herpes Simplex Virus Entry into HeLa and Chinese Hamster Ovary Cells

“…Fusion of bound virus with host membranes is thought to be triggered by the interaction with gD receptors. Studies of HSV-infected cells at early times postinfection using electron microscopy (EM) have detected virions fusing with the plasma membrane (16,17,34,40,50,51), as well as virions inside membrane-bound vesicles (6,11,13,17,23,40,51). On the basis of morphological analyses alone, it is not possible to assess whether any given virion is engaging a pathway that could lead to infection.…”