Attempted Chemical Isolation of the Virus of Poliomyelitis

Abstract

The demonstration of the chemical nature of the tobacco mosaic virus by Vinson and Petre, its recent isolation as a crystalline protein by Stanley, and the experiments of Howitt indicating that the virus of poliomyelitis may be also a chemical entity, have led us to employ Stanley's procedure in an attempted isolation of the virus of poliomyelitis in the form of a crystalline chemical substance. This attempt was not successful but, because the results are of interest in that they afford added evidence for the theory of the chemical nature of viruses, they are briefly reported herewith. One hundred grams of spinal cords from monkeys infected with the M.V. strain and developing typical paralysis in from 7 to 11 days after intracerebral inoculation, were finely ground with sand and extracted overnight in the refrigerator with 500 cc. of a solution of disodium hydrogen phosphate at pH 8. The thoroughly mixed suspension was poured onto a fine wire screen and the retained precipitate again extracted for 24 hours with 500 cc. of the phosphate solution, poured through the screen and the combined milky suspensions filtered by gravity through coarse fluted filter paper. A monkey inoculated with 0.5 cc. of this filtrate developed typical paralysis in 9 days. The filtrate was weighed and sufficient solid ammonium sulfate added to bring the final concentration to 30% by weight. The precipitate of crude globulin was separated by gravity filtration and extracted twice with 500 cc. portions of phosphate solution at pH 8. The combined filtered extracts were again precipitated with ammonium sulfate at 30% concentration and again extracted with two 500 cc. portions of phosphate solution. The combined filtered extracts were now precipitated with ammonium sulfate at 20% concentration and the globulin dialyzed against distilled water until free from sulfate.