Propagation of Poliomyelitis Virus in Cultures of Monkey and Human Testicular Tissues.

SummaryIn experiments in which monkey or human testicular cells in tissue culture were infected with poliomyelitis virus, Lansing and Yale-SK strains, proof was obtained that the virus in 3 passage series had been propagated. At the time this report was written it had been established for these 3 passage series that the minimal dilution factor based on tissue replacements ranged from 1014.6 to 1018 and, when assessed by fluid replacement, from 1029 to 1036. The LD50 of each strain of virus was determined on successive transfers, and the identity of each strain of virus was established by neutralization tests and histopathological findings in monkeys dead from the injection of tissue culture virus. Control experiments and other tests made known that propagation of poliomyelitis virus did not occur in the absence of viable testicular cells and that an extraneous virus was not inadvertently acquired during the course of these studies. It is plain that the results of the present investigation substantiate the observations of other workers that poliomyelitis virus can propagate in extraneural tissues. From these findings it is apparent that the assumption of an obligate neurotropism for poliomyelitis virus no longer is tenable. This observation and the demonstration regularly of the natural occurrence in poliomyelitis of virus in the oro-intestinal tract emphasize the need for a renewal of investigative studies of the factors that make possible invasion of the central nervous system to result in the overt and residual manifestations of poliomyelitis.