Biomaterial Database

Laboratory characteristics of attenuated influenza viruses. 1969

A S Beare

The selection of attenuated mutants of a virus related to A2/Tokyo/3/67 and of the subtype A2/Hong Kong/1/68 is described. By passing the former in the presence of heated horse serum it was possible to obtain a strain wholly resistant to thermostable horse-serum inhibitor. A2/Hong Kong/1/68 was, however, rendered only partially resistant by this technique. In subsequent volunteer trials it was clear that inhibitor-resistance was a marker of attenuation. Residual inhibitor-sensitivity was associated with some remaining pathogenicity. Inhibitor-resistant viruses were infective and antigenic.Inhibitor-sensitive viruses were also attenuated by repeated passage at 25 degrees C. When this was attempted with the partially inhibitor-resistant form of A2/Hong Kong/1/68, the virus became over-attenuated.In the laboratory, inhibitor-resistant viruses were shown to elute more rapidly from red blood cells than their inhibitor-sensitive parents and to grow better at 40 degrees C.

UI	MeSH Term	Description	Entries
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009975	Orthomyxoviridae	A family of RNA viruses causing INFLUENZA and other respiratory diseases. Orthomyxoviridae includes INFLUENZAVIRUS A; INFLUENZAVIRUS B; INFLUENZAVIRUS C; INFLUENZAVIRUS D; ISAVIRUS; and THOGOTOVIRUS.	Influenza Viruses,Myxoviruses,Orthomyxoviruses,Influenza Virus,Myxovirus,Orthomyxovirus
D006736	Horses	Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.	Equus caballus,Equus przewalskii,Horse, Domestic,Domestic Horse,Domestic Horses,Horse,Horses, Domestic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014774	Virulence	The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.	Pathogenicity
D014776	Virus Cultivation	Process of growing viruses in live animals, plants, or cultured cells.	Viral Cultivation,Cultivation, Viral,Cultivation, Virus,Cultivations, Viral,Cultivations, Virus,Viral Cultivations,Virus Cultivations