LIVE POLIO IRUS VACCINES

DR. BARON: When we come to the problem of
getting enough virus for stools to do intrathalamic
and intramuscular tests on monkeys, I am
reminded of some of Dr. Logrippo's work a num-
Discussion
133
Discussion 133
DR. BARON: They are too preliminary to report ber of years back. He described the use of
as yet.
barrels of stools, passaged through resin columns,
in order to concentrate virus efficiently in attempts
to obtain poliovirus CF DR. MELNICK: Are they negative?
antigens.
DR. BARON: They are plus-minus.
DR. SABIN: I should like to point out that in
the course of work with excreted attenuated
viruses, which goes back many years, all the
initial work was always done with the original
stools. We went on from work with the original
stools to first tissue-culture passages only when
it was found that original stools exhibiting no
change nevertheless exhibited altered behavior
when first tissue-culture passage was used, for
the simple reason that larger amounts of virus
were needed for the test.
This is particularly true when the intrathalamic
inoculation of monkeys is used. With
original stools inoculated intrathalamically, with
the amounts of virus that are present there, and
with the strains most recently used, it has not
ever been possible to get anything on intrathalamic
inoculation. The reason for going on to
first monkey-kidney tissue-culture passage was to
obtain the larger quantities of virus in which
changes could then be demonstrated.
Testing original stools is, therefore, not new.
It was the original procedure used many years
ago. There is in the literature very extensive
data reported on what has been found, using
original stools.
Culture passages, to repeat, are used to test
the large populations of virus particles.
DR. BODIAN: I think Dr. Sabin satisfactorily
explained the reasons for his going to passage
material, but 1 should like to emphasize, from
Dr. Baron's very meticulous study, the demonstration
that where titers of virus in stools are
at a satisfactory level, it becomes important to
use Dr. Sabin's original method of using stool
suspension rather than subcultured virus.
DR. SABIN: This is never-ending, but I believe
that the best thing to do, for anyone who is interested,
is to analyze quantitatively the data that
are amply reported in the literature. There is
quite a difference between using the intraspinal
technique, where we know that one can have
virus producing paralytic effects in rather small
doses, while a million tissue-culture infective
doses of the same virus given intrathalamically
may be without paralytic effect.
This is not the place to go over work that has
been covered in the last five or six years; it is
already recorded in literature, and anyone who
wants to follow up should cover the literature
which is on record.
DR. BODIAN: I should like to remind Dr. Sabin
that information on all of the strains which are
before us for consideration is not available on
this point.
CHAIRMAN ZHDANOV: We shall now proceed
with the paper by Dr. Verlinde on "Epidemiological
and Virological Survey Following Oral
Administration of Live Poliovirus Vaccine."