An effective candidate vaccine against respiratory tract infection was prepared with outer membrane proteins extracted from Mycoplasma hyopneumoniae and Pasturella multocida by the immunostimulating complexes(ISCOM) adjuvanted with Quil A, ISA50
and
Al(OH)3 respectively. The eight-week-old pigs were twice intramuscularly immunized the vaccines. The pigs were challenged intranasally with 5×10E7 color changing unit of M. hyopneumoniae J101 strain on 10 day a after second vaccination, and
followed by
6×10E7 CFU/ml of P. multocida type A. To compare the lymphocyte subpopulations in pripheral blood between vaccinated and unvaccinated group, lymphocytes were reacted with a panel of monoclonal antibodies which are specfic to swine leukocyte
surface
antigens and assayed by the flow cytometry. Proportions of cells expressing CD2, CD4, CD8, CD11a, CD45, and sIgM were decreased by adminstration of virulent M. hyopneumoniae and P. multocida in unvaccinated group. Howere, significant
cell-mediated
immune responses were induced in pigs treated with Quil A-ISCOM. The highest antibody titers against M. hyopneumoniae and P. multocida were obtained in ISA50 adjuvant group. Isolation of M. hyopneumoniae from lung tissue has shown that
microorganisms
were not found in vaccinated, but found in unvaccinated group, respectively.
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