LIVE POLIO IRUS VACCINES

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Safety-Laboratory Evidence of Attenuation and Safety
In the animals that died intercurrently nueronophagia
as well as acutely damaged ganglian
cells were found. The neuronophagia was
of leucocytic and microglial nature. In the
course of the inflammatory reactions pronounced
diffuse and nodular proliferations of microglia
as well as perivascular infiltrations of lymphocytes
and plasma cells were seen.
The topography of alterations, partly extending
up to the precentral gyrus, was characteristic
of poliomyelitis. In cases in which the lumbar
and cervical cord were involved, the thoracic
cord usually also contained lesions, even though
less pronounced. The distribution of specific
alterations thus corresponded to the typical distribution
in poliomyelitis. The animals in which
the virus had not been injected into the spinal
cord grey matter showed no lesions of poliomyelitis.
Histologically the following differences
in neuropathogenicity of the strains examined
were found:
Type 1 I.S. inoculation. All of the animals
showed alterations in the lumbar section which
obviously were not merely of traumatic nature.
The alterations found with the Sabin strain were
not as extensive and severe as with Cox's strain.
Here the alterations reached up to the brain
stem in six cases, in two animals up to the precentral
gyrus. With the Sabin strain the process
extended up to the cervical cord twice and
once up to the brain stem. Following I.C. inoculation,
alterations were missing in both groups.
Type 2 I.S. inoculation. In all animals the
alterations of the lumbar region already described
were found. With the Sabin strain an
extension of the process up to the brain stem
was seen in two animals. With the Cox strain
the process almost invariably extended up to the
brain stem, partly up to the precentral gyrus.
Clinically a slight paralysis of the arms was seen
in four cases. Following I.C. inoculation there
were no histological alterations with the Sabin
strain. With Cox's strain alterations were found
in most of the animals at the predilection sites of
poliomyelitis. Intensity and extent of the lesions
showed no significant relationship to the virus
concentrations administered. Histological findings
were as described above, motor weakness of
extremities could not be observed with certainty.
Type 3 I.S. inoculation. In the lumbar area
all of the animals had the usual lesions. With
the Sabin strain the process in three animals
extended up into the cervical cord, in two others
lesions of the central gyrus were found.
With Cox's strain 5 of the 13 animals inoculated
showed alterations characteristic of polio
up to the precentral gyrus.
Following I.C. inoculation there were no pathological
changes with the Sabin strain. Following
inoculation with the Cox strain alterations
reaching down to the lumbar area were
found in three animals.
1
TABLE 2.
TYPE 2
No. of monkeys with polio lesions / No. of inoculated monkeys