Figure 2: Expression of M2e from L. lactis. A serial dilution of LL-M2e washed cells was bound to a 96-well microtiter plate and analyzed by ELISA. Cell surface-bound M2e was detected by adding a constant amount/well of preimmune (▲) or postimmune (■) rabbit polyclonal M2e antiserum. Expression of M2e protein on the surface of LL vector with no M2e gene was not detected using preimmune and polyclonal antibodies (data not shown). The signal was developed with secondary antibody anti-rabbit IgG-horseradish peroxidase conjugate and chemiluminescent substrate. Error bars indicate standard deviation. Three independent experiments were conducted ().