Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/22/2002
Publication Date: 5/15/2002
Citation: ZEHR, E.S., TABATABAI, L.B., FRANK, G.H. IDENTIFICATION OF IRON-REGULATED OUTER MEMBRANE PROTEINS OF MANNHEIMIA HAEMOLYTICA BY COMPARATIVE 2-D ELECTROPHORESIS, WESTERN BLOTTING, AND MALDI-TOF (POSTER PRESENT. - 102ND MEET. OF THE AM. SOC. FOR MICROBIOLOGY). AMERICAN SOCIETY FOR MICROBIOLOGY ANNUAL MEETING. Salt Lake City, UT, May 18-23, 2002. Abstract # K-106.
Technical Abstract: Mannheimia haemolytica (MH) inhabits the tonsils and nasal passages of healthy cattle as a small portion of the normal bacterial flora. After transport or during viral-induced illnesses, MH serotype A1 can undergo a rapid, selective growth in the nasopharynx and proceed to cause acute pneumonia. Vaccination with MH possessing expressed that iron-regulated outer membrane proteins (IROMPs) has inhibited colonization of the nasopharynx. In vaccinated cattle, antibodies to IROMPs correlated with inhibition of MH colonization. A common mechanism for pathogens to obtain iron from the host is to up-regulate iron acquisition proteins. To study the role of IROMPs in colonization of the nasopharynx, IROMPs were isolated and identified. OMPs from MH grown in iron-restricted (brain heart infusion broth containing 2,2'-dipyridyl) and in iron-replete broth were treated with DNase and RNase, then precipitated with trichloroacetic acid. OMPs were subjected to 2-D electrophoresis and compared using BioRad's PD-Quest software. OMPs that were up-regulated in the iron-restricted medium (presumably IROMPs) were determined to be non-immunoreactive or immunoreactive by Western blotting using convalescent bovine antiserum as a probe. Selected IROMPs were picked from gels, digested with trypsin, and analyzed by MALDI-TOF for identification using Prospector's MS-FITsoftware. Thus far, two of the selected immunoreactive IROMPs have been identified as transferrin binding proteins, TbpA and TbpB. Additional up-regulated proteins are homologous to heat shock proteins and transcription regulators of several bacterial species. We have identified some non-immunoreactive and immunoreactive IROMPs of MH. The proteins may be further utilized to study their role in MH colonization of the nasopharynx.