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Cold adaptation of parainfluenza virus type 3: Induction of three phenotypic markers
Author(s) -
Belshe Robert B.,
Hissom Frances K.
Publication year - 1982
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.1890100403
Subject(s) - biology , virus , virology , mutant , clone (java method) , cold sensitivity , population , attenuated vaccine , common cold , serial passage , strain (injury) , wild type , temperature sensitive mutant , gene , genetics , virulence , immunology , demography , anatomy , sociology
In order to attenuate parainfluenza type 3 virus, a wild type strain that was isolated from a child with respiratory disease was adapted to replicate in African green monkey kidney cells at 20°C. Replication at 20°C was not a property of the wild type virus. The virus was serially passaged 45 times in the cold, and clones were selected following passage levels 7, 12, 18, and 45. The population of cold‐adapted virus was found to be progressively enriched with temperature sensitive (ts) mutants. After 7 passages in the cold, 1 of 9, and after 12 passages in the cold, 3 of 12 clones were temperature sensitive. Following 18 passages in the cold, 80% of the clones were temperature sensitive and after 45 passages in the cold, all clones were temperature sensitive. In addition to being temperature sensitive each ts clone manifested the tiny plaque morphology. Each temperature‐sensitive clone was also cold adapted. Some clones were cold adapted but were not temperature sensitive. The mutants were found to be genetically stable when serially passaged at 32°, 35°, or 39°C. The mutants may possess the necessary degree of attenuation for use as live attenuated intranasal vaccines.