LIVE POLIO IRUS VACCINES

Application of Genetic Markers to Development and Control of Vaccine 55
TABLE 2. INTRATYPIC SERODIFFERENTIATION TEST WITH VIRUSES REPRESENTING PASSAGE OF CHAT
STRAIN THROUGH
HUMAN INTESTINAL TRACT
VIRUS HUMAN % CONTROL PLAQUE DIAMETER UNDER ANTI-CHAT SERUM
PASSAGE
CHAT
O
B 117 1 . 10
Q-2 3 0
plaques without serum overlay. No differences
were observed between the first and third human
passage of the CHAT virus.
The actual results of the intratypic serodifferentiation
test applied to virus isolated in Leopoldville
are shown on Table 3. Virus isolated from
two healthy vaccinated infants showed serologic
TABLE 3. MARKERS AS DETECTIVE AGENTS. INTRA-
TYPIC SERODIFFERENTIATION TEST OF TYPE 1
POLIOVIRUSES ISOLATED FROM INHABITANTS OF
LEOPOLDVILLE DURING VACCINATION CAMPAIGN
WITH CHAT TYPE 1 VIRUS
GROUP
Vaccinated
SUBJECTS
CONDITION
Healthy
Sick
% CONTROL PLAQUE*
DIAMETER UNDER
ANTI-CHAT
SERUM OVERLAY
O
10
32
36
38
Sick 32
36
40
Non- 43
Vaccinated 45
48
t 50
50
* Positive control results (CHAT virus)-0%.
Negative control results (Mahoney virus)-0%
identity with the CHAT virus. In contrast, virus
isolated from three infants who became sick after
vaccination and from eight non-vaccinated paralytic
cases, seem to be unrelated serologically to
the CHAT virus, since the reduction in plaque
diameter under anti-CHAT serum overlay did
not exceed, in general, that observed with the
heterologous Mahoney virus.
Another opportunity to investigate strains isolated
during a vaccination campaign arose in
Poland. Preliminary clinical and epidemiologic
observations of this mass vaccination campaign,
during which the entire country was immunized
with the CHAT and Fox viruses, will be presented
by Dr. Przesmycki. Strains isolated from
six non-vaccinated children and three vaccinated
children, all of whom who showed symptoms of
disease, were submitted to our laboratory for
identification, following preliminary typing in
the Warsaw Laboratory. The results of the intratypic
serodifferentiation test against anti-
CHAT serum are shown in Table 4. They indicate
clearly that all nine strains are as unrelated
to the CHAT virus as was the Mahoney
virus which was employed as the negative control
in this test.
A summary of intratypic serodifferentiation
tests with Type 1 poliovirus isolated during vaccination
programs in Moorestown, Leopoldville,
and Poland is given in Table 5. All seven strains
isolated from subjects who were either fed the
CHAT virus or were in familial contact with
those fed the virus in Moorestown showed serologic
identity with the CHAT virus. Similarly,
Type 1 virus isolated from two individuals in
Leopoldville who exhibited no symptoms follow-