The transference of immunity from ewe to lamb / by T. Dalling, J.H. Mason, and W.S. Gordon.

  • Dalling, Thomas.
Date:
[1928?]
Catalogue details

Licence: In copyright

Credit: The transference of immunity from ewe to lamb / by T. Dalling, J.H. Mason, and W.S. Gordon. Source: Wellcome Collection.

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    S3 R WL [Reprinted from the Proceedings of the Royal Society of Medicine, 1928, Vol. XXI (Section of Comparative Medicine, pp. 31—32).] THE TRANSFERENCE OF IMMUNITY FROM EWE TO LAMB. By T. Dalling, J. H. Mason, and W. S. Gordon. DURING the course of our researches into lamb dysentery we devised a method of protecting lambs from dysentery by the inoculation of the mother sheep with a toxin-antitoxin mixture, prepared from the toxin of an anaerobe isolated from lesions in naturally infected lambs. Field results bear out that lambs are protected by such a method: thus in 1926, 2*34 per cent, of lambs born from inoculated ewes died of lamb dysentery, while 18*44 per cent, of lambs from uninoculated ewes died. The figures for 1927 are 0*87 per cent, of lambs from inoculated ewes died, while 8 • 04 per cent, of lambs from uninoculated ewes developed lamb dysentery. We have carried out a series of experiments which show that the inoculation of ewes with the above mixture causes the formation of antitoxin in their serum and that lambs born from such sheep have a similar amount of antitoxin. Method of Testing Serum for the Presence of Antitoxin. A standard toxin was made by growing the anaerobe in meat broth for 12-15 hours, filtering through paper pulp and sand and then through a Berkefeld filter. The filtrate is precipitated with ammonium sulphate, the precipitate isdried in vacuo and the residue is finely powdered. A weighed amount of this powdered toxin is dissolved in saline solution when tests are to be carried out. The toxin in this powdered form has retained its toxic and other qualities for many months. Experiments were carried out to determine the minimum lethal dose of the toxin by the mouse intravenous method, and the minimum skin-reacting dose by the guinea- pig intradermic methods. The smallest amount of toxin causing the deaths of mice and causing skin reactions in guinea-pigs, was used in the testing of the antitoxic content of the sheep sera. Fatal or reacting doses or multiples of them are mixed with 0 • 2 c.c. of serum, the mixtures allowed to stand at room temperature for about one hour and then injected into mice intravenously or into guinea-pigs intra- dermically; results are read in the mouse experiments in twenty-four hours and in the guinea-pig tests forty-eight hours later. Testing of Serum from Inocidated Sheep. Tests of many samples of serum from inoculated sheep have been made. Table I is the result of tests carried out on samples from ten sheep which were brought to the laboratory for inoculating and testing. These sheep were injected twice during pregnancy and were bled before injecting, after the first inoculation, and on several occasions after lambing. No antitoxin could be demonstrated in any sample obtained before injecting, while in three sheep after one injection, 0*2 c.c. serum protected against one fatal dose of toxin. Of the ten sheep, three failed to develop any detectable antitoxin after the second injection. Sheep 41 is of interest in that it showed the presence of antitoxin after one, but not after two injections. On the day it received its first injection it was necessary to administer 40 c.c. hyper¬ immune serum. Our test therefore detected passive immunity.