RELATIONSHIP BETWEEN THE DEGREE OF
REACTION AND IMMUNITY IN SERUM
SIMULTANEOUS INOCULATION IN
RINDERPEST
BY
K. S. NAIR, G.B.V.C., M.R.C.V.S., D.T.V.M.
Superintendent, Serum Institute, Madras
D. NILAKANTA AYYAR, G.M.V.C.
AND
A. R. MADHUSUDAN, G.M.V.C.
Veterinary Assistant Surgeons, Serum Institute, Madras
(Received for publication on 10th July 1939)
A ' BLOCKED-OUT ' reaction, which is brought about by giving massive
doses of serum in animals inoculated by the serum simultaneous method
against Rinderpest, has been suggested as a possible cause for the breakdown
of immunity.
Apart from the question of cost, this blocked-out reaction would be an
ideal method of immunization provided the production of immunity is not
interfered with, since the temporary inconvenience and the risk of a severe
reaction could be obviated.
In order to find out if it is at all possible to block out the reaction and at
the same time confer immunity to the inoculated, the following experiment was
undertaken.
At the outset, it was necessary to find out the required dose of serum that
would bring about a blocked-out reaction to a fixed dose of virus. Susceptible
young buffalo-calves were selected and were injected with 1 c.c. of virulent
Rinderpest virus simultaneously with serum at rates of 25, 30, 35, 40, 45 and
50 c.c. per 100 lb. body-weight. The results are summarized in Table I.
It is observed that the reactions are not blocked out with doses up to 35
c.c. per 100 lb. body-weight. Higher doses do block out the reaction but with-
out in any way interfering with the production of immunity. All the animals
under experiment were tested with a 5 c.c. dose of virulent bull virus at varying
intervals ranging from 13 to 44 days and they have been found to possess a
solid immunity as judged from the absence of any Rinderpest reactions after
the test dose of virus.
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