Bronchoalveolar lavage is an ideal tool in evaluation of local immune response of pigs vaccinated with Pasteurella multocida bacterin vaccine

The aim was to study the bronchoalveolar lavage (BAL) technique in evaluating the local immune response of pig immunized with Pasteurella multocida bacterin vaccine. Weaned piglets were immunized with formalin-inactivated P52 strain of P. multocida bacterin and evaluated for pulmonary immune response in BAL fluid. BAL was performed before vaccination and at different post vaccination days. The BAL fluid was assayed using enzyme-linked immunosorbent assay to study the development of P. multocida specific antibody isotypes and also evaluated for different cell populations using standard protocol. The average recovery percentage of BAL fluid varies from 58.33 to 61.33 in vaccinated and control group of piglets. The BAL fluid of vaccinated pigs showed increase in antibody titer up to 60(th) days post vaccination (8.98±0.33), IgG being the predominant isotype reached maximum titer of 6.12±0.20 on 45(th) days post vaccination, followed by IgM and a meager concentration of IgA could be detected. An increased concentration of the lymphocyte population and induction of plasma cells was detected in the BAL fluid of vaccinated pigs. Though intranasal vaccination with P. multocida plain bacterin vaccine could not provoke a strong immune response, but is promising as lymphocyte population was increased and plasma cells were detected. BAL can be performed repeatedly up to 3/4 months of age in pigs to study pulmonary immune response without affecting their health.