EXPRESSION OF IRON-REGULATED OUTER-MEMBRANE PROTEINS BY PORCINE STRAINS OF PASTEURELLA-MULTOCIDA

The outer membrane protein (OMP) profiles of two strains of capsular t ype A Pasteurella multocida isolated from the lungs of pigs with enzoo tic pneumonia were studied, Sarkosyl extracted OMPs from P. multocida grown under iron-restricted and iron-replete conditions were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and West ern blot analysis, Results showed that the iron-regulated outer membra ne proteins (IROMPs) with molecular masses of 74 kDa, 94 kDa, 99 kDa a nd 109 kDa were expressed by strain A52, while 74 kDa, 82 kDa, 94 kDa and 99 kDa IROMPs were expressed by strain B80, Swine immune sera, obt ained from pigs which were first immunized with a polyvalent P, multoc ida type A and type D bacterin and subsequently challenged with type A strain of P, multocida, contained antibodies against the IROMPs. Thes e antibodies cross-reacted with the IROMPs expressed by avian strain P 1059 of P, multocida. Convalescent-phase serum obtained from turkeys w hich survived fowl cholera, also crossreacted with the IROMPs from por cine strains of P, multocida. These results suggested that IROMPs from porcine and avian strains of P, multocida may share common epitopes t hat were recognized by swine immune serum as well as turkey convalesce nt-phase serum,