LIVE POLIO IRUS VACCINES

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Discussion
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FIG. 2
In the case of the strip which has an antibodynegative
serum on it, an almost straight line is
plotted. The bottom space moves somewhere
around 400 counts per minute and stays at this
level all the way up the strip, reaching 300 counts
per minute at the top of the strip.
In contrast to this, when 0.1 ml. of serum with
a neutralizing antibody titer of 1:32 (as judged
by cytopathogenic methods) was put on the second
strip (space 3), the spread of radioactive
virus is retarded (is kept down), and it piles up
on the lower spaces. It starts out at a count
about 1,000 per minute, then plots a curve that
goes down to under 100. This whole procedure
takes about eight minutes for the counting.
I wish to point out that we could merely have
counted the bottom few spaces of the strip or the
top few spaces, which would have taken only a
minute or so, and the proper answer would have
been obtained.
A mathematical expression can be found for
the curve of radioactivity of the immune serum
strip and a second one for the antibody-negative
strip. We therefore believe this to be a reproducible
physical phenomenon.
Figure 3 shows other examples of the effect of
specific antibody on movement of radioactive
Type 1 poliomyelitis up the paper strips.
DR. GARD: I should like to ask Dr. Vonka
whether he has tested the stability of the two
different activities he measured, the pH inhibition
and the cytopathogenic inhibition in some other
sera showing the greatest discrepancy; for instance,
permanent stability of the two factors and