Feasibility of propagating poliovirus in non-primate tissues

Tests concerning the feasibility of propagating poliovirus in non-primate tissues were conducted over a period of two years. The purpose of these tests was to determine whether the cellular specificity of polioviruses was limited to cultures of primate tissues. Mouse and calf kidney cells were grown in bottles and transferred for several generations. Cells from each new generation were challenged with type II MEF-1 strain poliovirus. The monkey kidney cell system was used for controls. The use of Melnick's medium containing only 2 percent calf serum resulted in thin elongation of the calf kidney cell after the sixth generation passage. Increasing the serum content in this medium to 4 percent aided the growth of the cells. The calf kidney cells grown in Melnick's medium containing 4 percent calf serum were more rounded yet still elongated after ten generations. The propagation of poliovirus was not detected in repeated experiments with freshly prepared as well as several subculture generations of either mouse or calf kidney cells by the method employed. It is possible as in the case of Capuchin monkey kidney cells that only a very small number of cells in any given populations would be susceptible to the virus. Any occurrence of a very small number of susceptible cells in a given population would result in a failure to observe any cytologic changes. It is possible that small numbers of cells, mouse as well as calf kidney, could have supported the growth of the poliovirus and gone undetected by the tissue culture tube method employed.