Study of herpes simplex virus type 1 populations obtained from recurrences and primary infections

Abstract

The analysis of 23 clinical isolates of herpes simplex virus type 1 (HSV-1) showed that 15 of 15 isolates that had undergone a few passages in tissue culture (fresh isolates) and two of eight isolates that had never been passaged (new isolates) were composed of a mixed population with respect to plaque morphology in Vero cells. Cloning and characterization of 10 large plaque viruses (L variants) and nine small plaque viruses (S variants), obtained from seven different isolates, showed the following. BamHI DNA restriction patterns of the L and the S variants from a single isolate differed only with respect to the electrophoretic mobility of the fragments that contain reiteration of specific sequences; they did not differ regarding the presence or the absence of restriction endonuclease cleavage sites. The L and S variants differed with respect to the electrophoretic profiles of infected cell glycoproteins, thermosensitivity of growth and plaquing efficiency at 39 degrees C, and, at least in the case of the two couples of variants that we tested, pathogenicity for the mouse. The hypothesis that the L variants might arise from the S variant during in vivo replication is discussed.

A block in glycoprotein processing correlates with small plaque morphology and virion targetting to cell-cell junctions for an oral and an anal strain of herpes simplex virus type-1

“…All three strains were grown in Vero cells to minimize cell-dependent differences [8,14,23]. Representative plaque isolates (based on plaque size and results of Western blot analysis of gC processing) were triple plaque purified on Vero cells to ensure clonality and used in these studies.…”

“…Although these viruses are replication competent, they exhibit very different tissue culture and biochemical behaviors than KOS, F and other large plaque strains [9,14,23]. KOS is also a model attenuated HSV-1 strain [18,36,38].…”

Experimental keratitis in rabbits by human HSV‐1 variants: Prevention and treatment

“…DISCUSSION Studies are described on the prevention and treatment of herpetic keratitis induced in rabbits by two HSV-1 variants, SV and LV, isolated at the first in vitro passage from a case of human herpetic keratitis. There were two observations of interest: (1) normally, plaque variants are detected after a few in vitro passages [Mannini-Palenzona et al, 1985;Costanzo et al, 19861, whereas SV and LV were simultaneously isolated at the first attempt to cultivate the clinical isolate; (2) a different pathogenic potential was evidenced: SV causes a benign keratitis and LV a lethal infection [Incorvaia et al, 19891. The fact that two phenotypic variants, genetically related, induce differ- The severity of keratitis was monitored and scored as described in the text and in Figure 2.…”

Further characterization of virus obtained from herpes simplex virus type 1 recurrences and primary infections. Influence of the temperature of incubation upon glycoprotein synthesis and virus release

“…New isolates 693 and 697 (two labial recurrences) were obtained from two different patients. The origin of the remaining new isolates and purified variants has been previously described (4). Vero cells grown in Eagle minimum essential medimn (MEM) supplemented with 5 per cent newborn calf serum were used throughout this study.…”

“…Vero cells grown in Eagle minimum essential medimn (MEM) supplemented with 5 per cent newborn calf serum were used throughout this study. Plaque morphology study, isolation of virus variants, serial passages of virus in T.C., and inoculation of mice have been previously described (4). Polyacrylamide gel eleetrophoresis of [~4C]glucosamine labelled cells was performed as previously described (1).…”