The titration of scarlet fever antitoxin in rabbits / by H.J. Parish and C.C. Okell.

  • Parish, H. J. (Henry James)
Date:
1927?]
Catalogue details

Licence: In copyright

Credit: The titration of scarlet fever antitoxin in rabbits / by H.J. Parish and C.C. Okell. Source: Wellcome Collection.

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    period than six days, almost always developed a purulent arthritis of one or more joints, from which a pure culture of the streptococcus could usually be obtained. With sera other than streptococcal no protection was obtained ; with various antistreptococcal sera, other than scarlatinal, from 17 to 29 per cent, of the rabbits were protected by doses of 5 c.cm. of serum. This group included unconcentrated sera prepared against streptococci of erysipelas, puerperal fever, and pyogenic infections. Seventeen rabbits were injected with 5 c.cm. of a serum prepared by immunisation with filtrates of a strain of Strepto¬ coccus pyogenes. Of these, 29 per cent, survived. This strain was isolated by Sir Frederick Andrewes from the septic finger of a nurse at St. Bartholomew’s Hospital. It produced a toxin which gave a reaction indistinguishable from the Dick reaction in Dick¬ positive individuals, but no reaction in Dick-negative individuals ; it had, therefore, a close antigenic relationship to the scarlet fever group of streptococci. Having found that specific scarlet fever antitoxins could be distinguished from other sera, an attempt was made to compare scarlet fever antitoxins of different values as tested by the Schultz-Charlton and passive immunity methods. Three pairs of sera which had been placed by means of human tests in “ order of merit ” were compared. Of two uncon¬ centrated sera, “ A ” was considered better than “ B ” on human tests. Serum “ A ” in a dose of 10 c.cm. turned 13 out of 14 “ Dick-positive reactors ” nega¬ tive within 24 hours, and 0-2 c.cm. of a 1 in 500 dilution blanched the rashes of 7 out of 15 patients. Serum “ B ” turned none of 4 patients Dick-negative, and blanched poorly the rashes of 4 out of 15 patients. In the rabbit test 15 rabbits were injected with each of the two sera in corresponding doses—viz., 10 c.cm., 5 c.cm., and 1 c.cm. Ten of the rabbits in the “ A ” batch survived, but 5 only in the “ B ” batch. The second pair of sera consisted of a concentrated batch, “ D,” and an unconcentrated, “ E.” By human tests it was found that with 2-5 c.cm. of serum “ D,” ten Dick-positive reactors became negative over night, and still gave a negative Dick test when retested on the twelfth day, whereas serum “ E ” in a dose of 10 c.cm. turned only 7 out of 10 patients negative. In the rabbit test the per¬ centages of survivals were at every dose higher for serum “ D ” than for serum “ E.” A dose of 1 c.cm. of serum “ D ” saved all three rabbits injected.