The use of mice in tests of immunity against yellow fever / by W.A. Sawyer and Wray Lloyd.

  • Wilbur Sawyer
Date:
1931
Catalogue details

Licence: Public Domain Mark

Credit: The use of mice in tests of immunity against yellow fever / by W.A. Sawyer and Wray Lloyd. Source: Wellcome Collection.

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    moribund or definitely ill 6 days after inoculation were anesthetized and bled from the heart. The mixed serum was injected intracerebrally, in the amount used in the previous experiments, intosixteennormalmice. Allof these mice remained well throughout the observation period of 14 days. The four mice whose blood had been taken for injection were killed and their brains were ground up together to make a 20 per cent suspension. Twelve mice were inoculated intraperitoneally each with 0.2 cc. of this suspension mixed with 0.4 cc. of normal human serum. Twelve other mice were similarly inoculated, but a known human immune serum was, substituted for the normal serum. All the mice were given also 0.03 cc. of 3 per cent starch solution intracerebrally. Of the mice receiving normal serum, one died early, and the remaining eleven died from 5 to 8 days after inoculation. Of the twelve receiving immune serum, all but one remained well for the entire observation period of 14 days. Thus was shown the presence of the virus in the brain and its identity as yellow fever virus. Evidently the virus had disappeared from the blood before the 6th day after inoculation and had not reappeared with the onset of the encephalitis and the production of much yellow fever virus in the brain tissues. While the evidence from these several experiments strongly suggests that yellow fever virus was present in the circulating blood of mice every day from the ist to the 5th after intraperitoneal inoculation and caused all, or most of, the deaths in the mice inoculated with the blood specimens, the presence of the virus has been confirmed by histo- logical examinations and subinoculations only for specimens of blood taken 24 hours, 48 hours, and 96 hours after inoculation. The evi- dence follows. Serum Taken after 24 Hours—(First supplementary experiment, Table V.) One of the mice which had been inoculated with the serum was killed when moribund, and part of its brain was examined histologically. There were definite lesions of encephalitis, typical of those seen in yellow fever in the mouse. Half of the same ,brain was ground up with half the brain of another mouse in the same group, and normal mice were inoculated intracerebrally with the suspension. Of twelve mice alive on the 3rd day after inoculation, eleven died from 4 to 9 days after inocula- tion, and the brain of one was examined and found to show pronounced and typical lesions of yellow fever encephalitis. Further subinoculations were made similarly from this group, and of seventeen mice alive on the 3rd day, fifteen died from 4 to 9 days after inoculation. The brains of two other mice of the group receiving the 24 hour serum were ground up together and used in inoculating eighteen mice intracerebrally. All of them died 4 to 6 days later. The brains of two were examined and found to show lesions of encephalitis. Blood Taken after 48 Hours —(Principal experiment, Series B, Table V.) Brain tissue of one of the mice which had received 48 hour blood was injected intracere-
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