Reactivation of Poxviruses by a Non-Genetic Mechanism

Abstract

IT has recently been shown that poxviruses inactivated by heat are reactivated in cells in which another poxvirus multiplies¹. The virus yield from cells infected with inactivated virus of one strain and active virus of another strain contains infectious particles of both strains, and also, if the viruses are sufficiently closely related, recombinants². Inactivation by heat, therefore, does not inactivate the deoxyribonucleic acid of the virus particles, since all the known genetic markers are preserved. Since proteins are in general less stable to heat than deoxyribonucleic acid, the role of the reactivating virus may be to provide some essential native protein which has been destroyed by heating. On this hypothesis, it should be possible to use, as the reactivating agent, virus of which the deoxyribonucleic acid has been specifically inactivated. In this case the genotype of the heat-inactivated virus only should survive.