Abstract
Summary
Development of a new type 3 attenuated poliovirus (WM-III) is described. Starting with the W-Fox strain, passage and clone selection at 23°C were employed to develop a strain with improved stability after human intestinal passage. The end result was a virus which had no capacity to grow at 40°C and was not virulent for monkeys injected intracerebrally. The results of tests of fecal virus strains isolated from infants fed the WM-III strain did not show the instability in relation to laboratory markers that has been reported with other attenuated type 3 viruses.
We wish to thank the following individuals for help in obtaining infants for vaccination, and supervising their care: Donald Comely, M.D., Paul Gyorgy, M.D., Jane Sitnek, R. N., Walter Omans, M.D., and Elizabeth Davies, R. N., Philadelphia General Hospital; and Agnes Flack, M.D., and Ruth Lorenzo, R. N., Clinton Farms. Toby Goldschneider and Suzanne Richardson assisted with laboratory work. Dr. George Jervis performed histological examinations of the monkey central nervous system.
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