Apparent "double mutation" induced by gamma rays.

RESULTS published by McLaren et al.1 indicated that the species specificity of poliovirus type 1 in tissue culture stemmed from the inability of the virus to absorb to non-primate cells. Infectious RNA from this agent was shown to initiate productive infections in cultured cells from a variety of warm-blooded animals2. More recently, it has been shown that mengovirus and a bovine enterovirus adsorb to cultured cells from several species and initiate infections which vary in efficiency of virus production from high to essentially nil3. The system which we are studying may resemble either or both of these models.