The immunity index method method of testing antigenic values / A.T. Glenny and Hilda Waddington.

  • Glenny, A. T.
Date:
[1928?]
Catalogue details

Licence: In copyright

Credit: The immunity index method method of testing antigenic values / A.T. Glenny and Hilda Waddington. Source: Wellcome Collection.

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    negative level within 8 weeks by weekly injections of Schick toxin, while other guinea-pigs have remained Schick positive after two years of this treatment. The average time is between 15 and 20 weeks. Commencing in July 1925, control tests were made at regular intervals and the results from over 200 guinea-pigs are summarised in table I which, with chart 1, shows that guinea-pigs are more readily immunised by small doses of toxin when immunisation is commenced in the summer or early autumn; at this period of the year fresh green food is more plentiful and this may afford a possible explanation of seasonal variation. In a similar way the rapid index method has been controlled by injecting normal guinea-pigs three times a week with Schick toxin. Over 20 such injections are needed on the average to immunise guinea- pigs by Schick toxin alone. The most rapid immunisation was that of one guinea-pig that became Schick negative after 13 injections. For this reason no rapid immunity index experiments are carried beyond 10 Schick tests, the guinea-pigs being discarded at this stage. Uniformity of results. Individual guinea-pigs vary in their power of response to an antigen and a number of animals must be used for each test; repeat tests made upon groups of 4 to 6 guinea-pigs on each occasion give fairly consistent results. Table II shows the results of 8 consecutive tests upon the same toxin-antitoxin mixture repeated every 3 weeks. On each occasion the majority of guinea-pigs gave an index of 2 or 2 to 3. Table II. Showing the immunity index of groups of 4 to 6 guinea-pigs each injected with 1*0 c.c. of the same toxin-antitoxin mixture. Date of test Immunity indices. 13th July .... 2 2 3 3 4 5 3rd August 2 2 3 3 4 4 24th August 2 2 2 3 4 4 14th September 2 2 2 2 5 over 10 5 th October 1 2 2 2 5 • • • 26th October . 2 2 2 4 5 over 10 16th November 2 2 2 5 • • • • • • 7th December . 2 2 2 5 ... ... A close analysis of similar results extending over two years has ■shown no evidence of seasonal variation. It is suggested that any possible seasonal variation in antitoxic response to such stimuli that induce potential immunity in about three weeks affects the degree of active response rather than the latent period elapsing before potential immunity is acquired. It is usually found that animals in poor condition are less readily immunised and, although it is not always so, as a general rule the A 2
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