title: Material for the study ofvariation in the Malayan Langat virus (TP-21 strain).
abstract: The lack of genetic uniformity of the Malayan Langat virus, TP-21 strain isolated from Ixodes granulatus ticks in Malaya, was demonstrated.Increased pathogenicity of the virus for white mice and rhesus monkeys after passage through chick-embryo fibroblast cultures at temperatures of 36 degrees C and 40 degrees C is due to the selection of the pathogenic virus particles which are always present in the initial brain-tissue suspension of the TP-21 Langat strain.The frequency of the occurrence of pathogenic clones and their selection rate was studied in relation to the conditions of cultivation. A study was also made of the genetic stability and basic biological properties of pathogenic and non-pathogenic clones of the Langat virus.
mesh_terms: D000818:Animals; D046508:Culture Techniques; D004669:Encephalitis Viruses, Tick-Borne / Q000472:pathogenicity*; D000882:Haplorhini; D051379:Mice; D014765:Viral Vaccines; D014776:Virus Cultivation
chemical_list: D014765:Viral Vaccines