Rn. Thwaits et S. Kadis, PURIFICATION OF SURFACE-EXPOSED INTEGRAL OUTER-MEMBRANE PROTEINS OF ACTINOBACILLUS-PLEUROPNEUMONIAE AND THEIR ROLE IN OPSONOPHAGOCYTOSIS, American journal of veterinary research, 54(9), 1993, pp. 1462-1470
Previously identified 39-, 50-, and 76-kd integral outer membrane prot
eins (IOMP) of Actinobacillus pleuropneumoniae, a respiratory tract pa
thogen, were separated by electroelution of sodium dodecyl sulfate-pol
yacrylamide gel electrophoresis-obtained fragments and their role in o
psonophagocytosis by porcine leukocytes was investigated by flow cytom
etry of fluorescein-labeled A pleuropneumoniae. Using specific antiser
a, immunoblot analysis indicated that the 3 proteins were antigenicall
y distinct. Antibodies against each iomp have an important role as ops
onins for phagocytosis by porcine leukocytes. The effect of using a co
mbination of all 3 of the specific antisera was minimal. Antiserum abs
orbed against intact A pleuropneumoniae and Escherichia coli organisms
indicated that the antibodies to the 39-, 50-, and 76-kd IOMP were sp
ecific for A pleuropneumoniae antigens. Nonheat-treated antiserum did
not increase phagocytosis, compared with heat-inactivated antiserum, i
ndicating that complement may not have a major role in opsonization of
A pleuropneumoniae.