Studies on Coxsackie B(5) Virus by Tissue Cultures Part 2. On the Plaque Mutants of Coxsackie B(5) Virus Obtained with Dog Kidney Cells

This paper describes briefly the results of experiments conducted with plaque mutants accidentally obtained in the course of the study of the multiplication pattern of Coxsackie B(5) virus with dog kidney cells (CS cell). 1. In the course of successive cultures carried out by having Coxsackie B(5) virus multiply in CS cells, a plaque mutant was obtained. In this instance, the plaque mutant could be classified into two kinds, one large and the other small one, and it was possible to form other clones by successive inoculation of each plaque to CS cells in cultures. 2. In the observations of the general properties of each strain obtained after clone formation, the findings suggest on the whole a P(S)→P(L) mutation phenomenon. 3. Even judging from the P(S)→P(L) mutation phenomenon, properties of Coxsackie B(5) virus a, e fairly well preserved, but the characteristics of the virus as confirmed by experiments dealing with the multiplication pattern of virus and by neutralization tests have revealed some changes. Especially with P(L) strain the mutation is firm, suggesting that a certain fixed condition is necessary under which the virus properties remain intact even in the presence of antiserum and similar mutant does not appear in the other cell strains.