STUDIES ON THE PURIFICATION OF POLIOMYELITIS VIRUS : I. YIELDS AND ACTIVITY OF PREPARATIONS OBTAINED BY DIFFERENTIAL CENTRIFUGATION.

Results of experiments on the preparation of high molecular weight constituents from normal and poliomyelitis-infected medullae-cords are presented. Relatively large yields were obtained from glycerolated normal or infected tissues or from tissues that had been stored at -10 degrees C. for a few days. When the frozen tissues were stored for several weeks, the amount of sedimentable nitrogen isolated from the normal cords decreased and became almost negligible. Under these same conditions small but definite amounts of a high molecular weight material were isolated from the infectious extracts. This material regularly produced poliomyelitis when 1 ml. containing 5 x 10(-9) gm. of nitrogen was injected intracerebrally into rhesus monkeys. The purified virus sediment contains nitrogen, phosphorus, and carbohydrate, it gives the Millon's test for protein, and is precipitated by one-third saturation with ammonium sulfate. Results of ultracentrifugal analyses show that a relatively homogeneous component with S(W) (20 degrees ) = 62 x 10(-13) is present.