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Cell wall components of L. monocytogenes and the sub-species of L. ivanovii
were analysed by SDS-PAGE and Western blotting. Preliminary studies demonstrated the
protein nature of blotted material. Difference's in the protein antigens of L.
monocytogenes (serotypes 4a and 4b) and L. ivanovii (serotype 5) were established.
Differences were not detected between proteins of serotypes 4a and 4b and serotype 7,
Cell wall proteins of L. monocytogenes grown at 20°C and 37°C were defined. Differences
of expression of proteins were noted, particularly with regard to a complex of 3
proteins of approximate molecular weight 29,000D expressed at 20°C but not at 37°C.
This complex was found to be referable to bacterial flagellin and the results support
the microscopic evidence for temperature dependent expression of flagella.
The production of an anti-flagellin monoclonal antibody allowed analysis of flagellins
from different serotypes. The monoclonal antibody detected the 29,000D flagellin of
serotypes l/2b, 3b, 4a, 4b and 4d but not the flagellins of serotypes 3c and 5 which
had a slightly lower molecular weight.
A study of cross-reaction of L. monocytogenes proteins with proteins of other bacterial
species was undertaken. Extensive cross-reaction was revealed between somatic antigens
of L. monocytogenes and proteins of S_. epidermidis, S_. aureus, Str. fecalis and B_. subtil
Serological studies revealed that convalescent serum from CBA mice recovering from a
primary challenge of flagellate organisms (1 x LD50 organisms intraperitoneally or
100 x ID50 organisms by the oral route) did not elaborate antibody against L. monocytoger
flagellin as determined by ELISA. In the same mice, antibody levels against L.
monocytogenes cell wall proteins were low and inconsistent.
Serum antibody levels in 14 field cases of ovine listerial encephalitis were measured
by ELISA. Titres against both L^. monocytogenes cell wall protein and flagellin were
of the same order as healthy control animals. Three out of 23 field cases had antilisterial antibody in the CSF. For two of these cases serum samples from the same
sheep were also available. By Western blotting it was shown that the same spectrum
of antibody was present in both serum and CSF.
Sheep recovering from experimentally induced L. monocytogenes septicaemia did not have
antibody levels, as measured by ELISA, significantly highter than normal uninfected
LD50 and ID50 experiments were conduced in CBA mice using flagellate and aflagellate
organisms of the same serotype. No difference in pathogenicity could be determined
by these methods. From these experiments it was possible to define the two syndromes
of murine Listeriosis, of early septicaemic death and late neurological dysfunction.
Nervous symptoms were recorded in 30% of mice which died, and the syndrome occurred
following either intraperitoneal or intragastric challenge with both flagellate and
Repeated vaccination of CBA mice with adjuvanted flagella failed to protect them against
a subsequent intraperitoneal challenge with flagellated organisms.