Monoclonal antibodies against Actinobacillus pleuropneumoniae TonB2 protein expressed in Escherichia coli.

TonB is known to be a bacterial periplasmic protein that transduces proton from the inner membrane to the outer membrane receptor in complex with the ExbB and ExbD proteins. Actinobacillus pleuropneumoniae TonB2 protein is the second TonB protein that is important for iron acquisition and virulence. The TonB2 protein was verified to be immunogenic and could afford partial protection for animals from lethal infection. In the present study, the recombinant TonB2 (rTonB2) was overexpressed in Escherichia coli BL21(DE3) and purified. The rTonB2 was then used as antigen to immunize BALB/c mice for the production of monoclonal antibodies (MAb). Four clones of TonB2-specific MAb secretion hybridomas--2F2, 2G8, 3D2, and 6F10--were selected. The MAbs 2F2, 3D2, and 6F10 were classified as IgG1 isotype and 2G8 was of IgG2a isotype. Western blot and ELISA results indicated that MAbs had specific binding activity to rTonB2. The MAbs generated here will be used for further functional analyses of the TonB2 protein.