MAJOR OUTER-MEMBRANE PROTEINS OF PASTEURELLA-HAEMOLYTICA SEROVARS-1-15 - COMPARISON OF SEPARATION TECHNIQUES AND SURFACE-EXPOSED PROTEINS ON SELECTED SEROVARS

The Sarkosyl method of obtaining outer membrane proteins (OMPs) from P asteurella haemolytica A1 was more efficient and less laborious than s eparating membranes by sucrose gradient centrifugation, More OMPs were recovered and major OMPs were present in greater concentrations in th e Sarkosyl-derived preparations. Therefore, OMPs of P. haemolytica ser ovars 1-15 (serovars 3, 4, 10, and 15 being T biotypes and the remaind er being A biotypes) were prepared by the Sarkosyl method and con?pare d by SDS-PAGE. Serovars 1, 2, 5, 6, 7, 8, 11, and 12 which are A biova rs had similar OMP profiles characterized by major OMPs of 30.5 and 43 kDa. Biovar T strains were characterized by doublet protein bands in the 26-28 kDa region and a major OMP in the 38-40 kDa range. Serovars 9, 13, and 14, which are also A biovars, had profiles similar, althoug h not identical, to the T biovars. A 43 kDa protein was present in all serovars although concentration was greater in the A biovars. Surface -exposed proteins of P. haemolytica A1 determined by I-125-labeling of whole cells were 94, 84, 53.5, 49, 43, 41, 29.5, and 16 kDa, Iodine-l abeling of serovars A2 and A6 which have similar OMP profiles by SDS-P AGE resulted in autoradiographs indistinguishable from A1. These studi es expand our knowledge of P. haemolytica OMPs especially showing the utility of the Sarkosyl extraction procedure, variations in OMP profil es among some A biovar strains, and the similarities of OMP profiles a nd surface-labeled proteins among three of the most important serovars (1, 2, and 6).