Studies on Inhibition of the Agents of Murine and Feline Pneumonitis by Penicillin

[摘要] Prolongation of the survival time of chick embryos infected in the yolk sac with the agent of murine pneumonitis was obtained with doses of 2 to 20 Oxford units of penicillin per egg. An increase in the dose of 4 to 15 fold allowed survival of all embryos for 12 days after inoculation.Inhibition of the development of the virus of feline pneumonitis was obtained with 20 to 2,000 units of penicillin per egg, or about 20 times as much as is required for comparable inhibition of the growth of the mouse pneumonitis virus.Infections of the yolk sac caused by the agent of mouse pneumonitis were sterilized by penicillin in doses of 100 units given 24 hours after infection. For a similar complete virucidal effect on the cat pneumonitis virus, 5,000 units given three times at 2, 72, and 144 hours after infection were necessary.When treatment was delayed the dose of penicillin required increased with the time after inoculation at which it was administered, but inhibitory and virucidal effects on the mouse pneumonitis virus were demonstrable with 5,000 units given 4 to 5 days after inoculation.In vitro virucidal effects by crystalline penicillin G at a concentration of 2,000 units per cubic centimeter were not demonstrable. Impurities of unknown nature in crude penicillin were virucidal in vitro for the mouse pneumonitis virus.

[学科分类] 生物科学（综合）