| Project/Area Number |
60870083
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
Biological pharmacy
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| Research Institution | Tokyo Metroplitan Institute of Medical Science (1987)
The University of Tokyo (1985-1986) |
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Principal Investigator |
NOMOTO Akio Tokyo Metropolitan Institute of Medical Science, 微生物研究部門, 部長 (70112670)
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| Co-Investigator(Kenkyū-buntansha) |
田子 勝彦 (財)日本ポリオ研究所, 理事長
ARITA Mineo National Institute of Health, 腸内ウイルス部, 室長 (90100065)
TAGO Katsuhiko Japan Poliomyelitis Research Institute
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| Project Period (FY) |
1985 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥14,500,000 (Direct Cost: ¥14,500,000)
Fiscal Year 1987: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1986: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1985: ¥10,000,000 (Direct Cost: ¥10,000,000)
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| Keywords | Polio live vaccine / Infectious cDNA clone / Transfection / Recovered virus / Recombinant virus / Serial passage / 免疫原性 / 感染性cDNAクローン / 神経毒性 / 抗原性 / 感染性相補DNAクローン / 組み換え体ウイルス / in vitro マーカー |
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| Research Abstract |
The rate by which spontaneous mutations occur is high in single-stranded RNA genome replication as compared to double-stranded DNA replication. The single-stranded RNA genome of poliovirus is not an exception to this high rate of mutation. One possibility for "stabilization" of the poliovirus genotype is to carry out large scale propagations of the genome as cDNA cloned into bacterial plasmids. Accordingly, we constructed full size cDNA of the Sabin 1 strain that is the safest polio vaccine strain. The virus produced in cells transfected with the cDNA showed biological characteristics indistinguishable from the parent Sabin 1 virus. Thus, we succeeded to store the genietic information of the attenuated Sabin 1 strain in double-stranded DNA.
For construction of type 2 and type 3 poliovirus vaccine strains in vitro, we took advantage of the infectious cDNA clone of type 1 poliovirus(Sabin 1 strain). Since molecular genetic analysis of the attenuation phenotype of type 1 poliovirus revealed that genome region coding for the viral capsid proteins had little correlation with neurovirulent phenotype of type 1 poliovirus, it was possible to replace the Sabin 1 genome sequence encoding the whole-coat proteins by the corresponding sequences of the Sabin 2 and Sabin 3 genomes. Indeed, the construction of such recombinant viruses was successful. The recombinant viruses were tested for their biological characteristics including monkey neurovirulence. In vitro phenotypes were found to be fairly stable after serial passages of the viruses. Furthermore, the viruses had ability to effectively elicit neutralizing antibody in monkeys and guinea-pigs.The results clearly indicated that these recombinant viruses were attenuated enough to be considered as candidate viruses of the oral polio livbe vaccines.
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