Purification of the Kilham rat virus.

A purification procedure is described for the isolation of Kilham rat virus (RV) from infected suckling hamster kidney and liver suspensions. The procedure involved a combination of sonic treatment, differential centrifugation, butanol-chloroform extraction, agar column flow diffusion, and potassium tartrate density gradient centrifugation. The purified virus retained its infectivity and was specifically neutralized by RV hyperimmune antiserum. Electron micrographs from the RV band (density 1.31 g/ml) showed numerous homogeneous particles approximately 22 mmu in diameter.