Isolation of a temperature-sensitive dengue-2 virus under conditions suitable for vaccine development

Infect Immun. 1976 Nov;14(5):1221-7. doi: 10.1128/iai.14.5.1221-1227.1976.

Abstract

Dengue virus, type 2, in viremic human sera and after passage in cell cultures produces mixtures of small and large plaques when assayed in LLC-MK2 cells. Clones of dengue virus type 2 obtained by plaque selection in primary green monkey kidney cell cultures were tested for temperature sensitivity in vitro and for virulence by intracerebral inoculation of suckling mice. Sublines of a small-plaque clone were found to have lower nonpermissive temperatures than the parent virus by both plaque formation and release of infectious virus into the culture media. Small-plaque sublines were significantly less virulent in suckling mice than was the parent virus. Sublines from a large-plaque clone were not temperature sensitive and closely resembled parent virus mixed-plaque morphology. When small-plaque sublines were serially passaged using undiluted inocula, reversion occurred as evidenced by the appearance of large plaques and return of mouse virulence. Small-plaque virus could be maintained through several serial passages without reversion by using low-input inocula. Desirable passage history as well as temperature-sensitive and attentuation characteristics of the S-1 small-plaque subline make it appear suitable as a vaccine candidate virus.

MeSH terms

  • Animals
  • Cell Line
  • Dengue Virus / isolation & purification*
  • Dengue Virus / pathogenicity
  • Genetics, Microbial
  • Humans
  • Mice
  • Temperature*
  • Viral Plaque Assay
  • Viral Vaccines / isolation & purification*
  • Virus Cultivation
  • Virus Replication

Substances

  • Viral Vaccines