FIG. 1.

M. bovis BCG and M. smegmatis were engineered to secrete a polyepitope, OVApet. A polyepitope, OVApet, was constructed to express the OVA_257-264 H2-K^b binding epitope downstream of the alpha antigen secretory signal from M. bovis BCG, which ensured it was secreted out of the bacteria (A). Lysates of wild-type M. bovis BCG (1), M. bovis BCG-OVApet (2), M. smegmatis (3) and M. smegmatis-OVApet (4) were run on a sodium dodecyl sulfate-16% reducing polyacrylamide gel, blotted onto a nitrocellulose membrane, and probed with an anti-PK monoclonal antibody followed by a biotinylated secondary antibody and then streptavidin-horseradish peroxidase. Expression of OVApet was detected by enhanced chemiluminescence (Fig. 1B). α-Ag, alpha antigen.