The Journal of Medical Microbiology, Vol 32, Issue 1 55-61, Copyright © 1990 by Society for General Microbiology
Outer membrane proteins of bovine strains of Pasteurella multocida type A and their doubtful role as protective antigens
M. Z. Abdullahi, N. J. Gilmour and I. R. Poxton
Moredun Research Institute, Edinburgh.
Outer membranes were prepared by the Sarkosyl method from 30 strains of
Pasteurella multocida and the closely related Taxon 13, which had been
isolated from cattle. The patterns of the outer membrane proteins (OMPs) on
SDS-PAGE were generally similar to one another, though the four major
proteins (a-d) varied somewhat in molecular mass; these patterns allowed
the strains to be arranged into 12 groups. Taxon 13 strains and typical P.
multocida strains were indistinguishable, both types being found within the
same group. Mice were vaccinated with heat-killed bacteria of three strains
and challenged with 10 LD50 of homologous and heterologous live bacteria,
representing groups based on OMP patterns; the best protection was afforded
by strain W674, which protected against nine of the 17 challenge strains;
but there was no correlation between protection and PAGE pattern.
Pre-vaccination and pre-challenge sera were used in immunoblotting to probe
OMPs from protective and non-protective strains. All three vaccines
produced antibody to proteins a and d; these proteins appeared to be common
to all strains, varying in molecular mass but not in overall antigenic
expression. The antibody response to the other two major OMPs appeared to
be PAGE-group specific. There was no correlation between protection and the
antigen pattern seen by immunoblotting.
