Attempt to Propagate Poliomyelitis Virus Through Serial Passage in Cotton Rats by "Spreading Factor of Duran-Reynals."

Abstract

Numerous attempts have been made to “adapt” poliomyelitis virus to passage in the eastern cotton rat since Armstrong1 reported that a strain of virus isolated from one of a number of cases occurring during an outbreak of poliomyelitis in Lansing, Michigan, could be propagated in the variety Sigmodon hispidus hispidus. These attempts, including those of Armstrong, to obtain takes with other strains of poliomyelitis virus have failed. Toomey2 has recently reported unsuccessful attempts to propagate 9 other monkey adapted strains of this virus. He inoculated 9 groups of Sigmodon hispidus littoralis rats, each with one of 9 strains of virus and later when symptoms failed to develop, these animals were shown to be susceptible to the Lansing strain.Duran-Reynals3, 4 has shown that testicular extract (“spreading factor”) added to the virus of vaccinia increased the extent of the lesions in the rabbit, and Hoffman and Duran-Reynals5 showed that it had similar enhancing effects on the viruses of herpes, vesicular ...