COXSACKIE A9 VIRUS: MUTATION FROM DRUG DEPENDENCE TO DRUG INDEPENDENCE.

During the multiplication of Coxsackie A9 virus dependent on 2 - (alpha - hydroxybenzyl) - benzimidazole there arise some drug-independent virus particles, which are either drug-resistant or drug-sensitive. We studied the properties of such revertant particles under conditions which did not favor the selection of resistant over sensitive virus particles. These particles exhibited a wide range of responses to 2-(alpha-hydroxybenzyl)-benzimidazole, from high sensitivity to high resistance. Subclones showed the same degree of sensitivity or resistance as the respective parent clones.