Immunological study of an attenuated Salmonella Typhimurium expressing ApxIA,ApxIIA, ApxIIIA and OmpA of Actinobacillus pleuropneumoniae in a mouse model

Salmonella Typhimurium strain expressing the Actinobacilluspleuropneumoniae antigens, ApxIA, ApxIIA, ApxIIIA and OmpA, was previouslyconstructed as a vaccine candidate for porcine pleuropneumonia. This strain was a liveattenuated (∆lon∆cpxR∆asd)Salmonella as a delivery hostand contained a vector containing asd. An immunological study oflymphocyte proliferation, T-lymphocyte subsets and cytokines in the splenocytes of a mousemodel was carried out after stimulation with the candidate SalmonellaTyphimurium by intranasal inoculation. The splenic lymphocyte proliferation and the levelsof IL-4, IL-6 and IL-12 of the inoculated mice were significantly increased, and the T-and B-cell populations were also elevated. Collectively, the candidate may efficientlyinduce the Th1- and Th2-type immune responses.