Hybrids derived from the viruses of variola major and cowpox

Bedson, H. S.; Dumbell, K. R.

doi:10.1017/s0022172400039887

Cited by 37 publications

(20 citation statements)

References 14 publications

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“…White pock mutants of cowpox have been studied extensively since their initial isolation in 1952, and nothing unusual was seen in their pock character as late as 1966 (Baxby & Rondle, 1967). In particular, attempts have been made to obtain parental red cowpox by recombination between strains of white cowpox (Bedson & Dumbell, 1964;Fenner & Greenland, 1964) and in these circumstances production of red pocks would surely have been noticed and investigated. These factors, plus the fact that atypical pocks have now been seen elsewhere (C. R. Madeley, 1969, personal communication), leads one to suggest that the phenomenon has not been missed previously but is of recent origin.…”

Section: Discussionmentioning

confidence: 99%

Variability in the characteristics of pocks produced on the chick chorioallantois by white pock mutants of cowpox and other poxviruses

Baxby

1969

Epidemiol. Infect.

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White pock mutants of cowpox virus produce pocks in the CAM which ‘mimic’ those produced by the parent virus, in macroscopic and microscopic appearance, and in the amount of virus they contain. The proportion of such ‘atypical’ pocks was influenced by the age and source of embryo, incubation temperature and position of the CAM during incubation. Similar results were obtained with white pock mutants isolated from strains of vaccinia, rabbitpox and monkeypox. The appearance of pocks produced by variola, alastrim, ectromelia and vaccinia (Lister) was unaffected by changes in environmental conditions.I would like to thank Professor K. McCarthy, Professor K. R. Dumbell, Dr C. H. Taylor-Robison and Dr C. R. Madeley for their interest and for kindly providing virus strains, and Miss M. Seyfang for technical assistance.I would like to thank the Committee on Research, Liverpool University, for a grant towards the cost of the colour plate.

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Section: Discussionmentioning

confidence: 99%

Variability in the characteristics of pocks produced on the chick chorioallantois by white pock mutants of cowpox and other poxviruses

Baxby

1969

Epidemiol. Infect.

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“…This finding is in great contrast with that of clones derived from the parent These findings may be best interpreted as that plaguing efficiency is controlled by multiple genes, and hence the genetic recombination between the two vaccinia viruses with different plaguing efficiencies for L cells results in recombinants with a variety of plaguing efficiency. Previous studies indicate ready occurrence of recombination between the members of the variolavaccinia group [1][2][3][4][5][6][7][8][9]12].…”

Section: Stability Of Properties Of Monotypic Clones From Mixed Infecmentioning

confidence: 99%

Genetic Recombination between Vaccinia Virus Strains Distinct in Hemagglutinin Production and Plaquing Efficiency

Ando

Matumoto

1968

Japanese Journal of Microbiology

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Oda (1965) reported the rescue of dermovaccinia (strain Dairen I) abortive infection by ncurovaccinia virus (strain IHD-T) in mouse fibroblastic L cells. The present study, however, provided no evidence for such, but gave evidence for the occurrence of genetic recombination between the viruses in L and HeLa cells. HeLa and L cells were infected simultaneously with strain Dairen I which produces hemagglutinin (H+) and replicates well in HeLa cells but only poorly in L cells, and strain IHD-T which is H-and multiplies well in both cells. Sixty-eight of 225 and 24 of 114 clone preparations from the mixed infection yields in L and HeLa cells, respectively, were mixtures of H+ and H-viruses. The remaining 157 and 90 clones contained only one type of virus, H+ or H-, and varied widely in the plaguing efficiency for L cells. This contrasted with the results from parent viruses. An interpretation is that the plaguing efficiency is controlled by multiple genes and genetic recombination between the two vaccinia viruses with differing plaguing efficiencies results in occurrence of recombinants demonstrating a variety of plaguing efficiency. Hemagglutinin production was an all-or-none character, no intermediates being found, and can readily be tested at the particle level by the plaque-hemadsorption technique. These points render hemagglutinin production as a suitable marker for the genetic studies in contrast to the polygenic plaguing efficiency.

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“…Two had haemorrhagic, ulcerated pocks, like those of cowpox, but the remaining 14 were chosen because their pocks differed from those of cowpox. The properties of these clones will be described in a subsequent paper (Bedson & Dumbell, 1964b).…”

Section: Reactivation By Heat-tethered Virusmentioning

confidence: 99%

The use of ceiling temperature and reactivation in the isolation of pox virus hybrids

Dumbell

Bedson

1964

J. Hyg.

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A simple method for the isolation of pox virus hybrids on the C.A.M. has been described. One parental virus was used as a heat-inactivated suspension. The other parent was used in the active state, but at a temperature higher than its ceiling temperature. Under these conditions the inactive parent was reactivated so that pocks resulted only from the cells infected with both parental viruses. Many of these pocks were unlike those of either parent. Such lesions were found to contain a high proportion of hybrids. In these experiments, alastrim was crossed with rabbit pox and variola major with cowpox.The term ‘heat-tethered’ has been used to describe virus whose intracellular cycle of development has been arrested by incubation at too high a temperature. Heat-tethered virus has interesting properties and two of these have been described. When the temperature is lowered, heat-tethered virus will start to grow again. Its reactivating potential has been mentioned above. A more detailed account of the properties of heat-tethered virus is being prepared.

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Hybrids derived from the viruses of variola major and cowpox

Cited by 37 publications

References 14 publications

Variability in the characteristics of pocks produced on the chick chorioallantois by white pock mutants of cowpox and other poxviruses

Variability in the characteristics of pocks produced on the chick chorioallantois by white pock mutants of cowpox and other poxviruses

Genetic Recombination between Vaccinia Virus Strains Distinct in Hemagglutinin Production and Plaquing Efficiency

The use of ceiling temperature and reactivation in the isolation of pox virus hybrids

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