LIVE POLIO IRUS VACCINES

A Physical Property as a Virus Marker
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paralytic poliomyelitis due to Type 1 poliovirus,
the isolates obtained from Dr. Paul's laboratory
all behaved in the way Mahoney does when
tested by the DEAE column. We also have
from Dr. Paul's laboratory five other strains
obtained from the experiment which was referred
to earlier, 1 believe, by Dr. Melnick.
These behaved as follows: Four of the five were
eluted in exactly the same way as is the Mahoney
strain, and published data from Dr. Paul's
laboratory indicate that the results of monkey
inoculation go along with this.
The fifth strain is again an intermediate strain.
It was one obtained from a child fed LSc, 2ab
strain some days earlier, and it did not produce
clinical disease in either of the two monkeys
inoculated, although it did produce lesions in
one of the two.
One other point might be mentioned: If one
takes the Mahoney eluate and puts it into a
capillary tube with hyper-immune rabbit serum,
a flocculation occurs either after an hour in the
incubator or overnight. This does not happen
when the LSc, 2ab eluate is tested. It may be
merely a difference in concentration of virus.
Another point of difference I should mention
is this: If we take the LSc, 2ab virus which
does come off the column, or the LSc, 2ab
which we can elute off the column by adding
saline, grow them in tissue culture, and then
put them through the column, they behave again
as does the original LSc, 2ab strain. The difficulty
of elution, therefore, appears to be a
characteristic of the strain and does not indicate
that there is a mixture. It seems to be a
characteristic which, through at least several
tissue-culture passages, is a constant one.
We have done a little work with the Type 2
strains, using the strain which Dr. Sabin has in
his vaccine. Using the buffer system, which I
have described, one cannot detect a difference
between the virulent and nonvirulent. The two
strains come out very much in the manner as
the Mahoney shown here.
However, if we use a different buffer system
with a low concentration sodium chloride, .05
molar in this buffer, then the same result occurs;
the virulent strain comes off the way the Mahoney
does. The vaccine strain behaves like
the LSc, 2ab strain in that it is held avidly by
the column.
To summarize, this marker we call the E, or
elution marker, appears to be a characteristic of
a particular strain. In other words, it has been
correlated with virulence or lack of it, as judged
by monkey inoculations.