LIVE POLIO IRUS VACCINES

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Discussion
specimens. We were using serology only for the
possibility of detecting infections by serologic
conversions that we had missed by excretion
studies.
Our interest was primarily on the spread phenomenon,
and therefore we were interested mainly
in the fecal excretion of virus. Therefore, I
readily admit we were using very crude measures
of antibody response.
Our own previous serologic studies are in
agreement with the comments that have been
made. We have seen low level responses that
were very transient in nature. Even if the blood
had been collected only a month later, these
would have been missed. Therefore, our data
really did not contribute very much on serologic
response and were not presented for that purpose.
DR. MELNICK: The need for a more sensitive
antibody test has been mentioned. We do have
such a test, and it was described yesterday, when
1 mentioned the antigenic differentiation test
which we use. Serum at varying dilutions is incorporated
in the agar over monolayer cell sheets,
and the virus challenge added as a disc on top
of the agar.
By this test the National Foundation sera,
which may have a titer of 1 to 1,000 or so in the
standard CPE neutralization test, yield titers of
over 1 to 300,000.
I do not recommend this test for ordinary use,
because it requires the bottle or plate technique,
but for very special purposes where one is looking
for a sensitive measure of antibodies, I think
it might be useful.
CHAIRMAN ZHDANOV: The next paper will be
presented by Dr. Kimball, on "Minnesota Studies
with Oral Poliomyelitis Vaccine. Community
Spread of Orally Administered Attenuated Poliovirus
Vaccine Strains." It will be followed by
Dr. Paul's presentation on "The Capacity of
Live Attenuated Poliovirus to Spread within
Families."