FIGURE 2.

Interactions of BspA with immobilized gp340. A, dot immunoblot to verify the expression of BspA on the surface of L. lactis NZ9800. Lactococci were cultured for 16 h in the absence (uninduced) or presence of 10 or 100 ng/ml nisin to induce BspA expression. Lactococcal suspensions (A_{600 nm} 2.0) were serially 2-fold diluted and spotted onto nitrocellulose membrane. The blot was probed with α-Spy1325 mid antibodies to the V region of AspA (25). B, binding of L. lactis pMSP.bspA⁺ or vector control (pMSP) to immobilized gp340. Induced or uninduced cells were then incubated in microwells coated with 50 ng of gp340 (black column) or blocking agent BSA (gray column) for 2 h at 37 °C. Nonadherent cells were removed, and total biomass was measured by crystal violet staining. Values given represent mean ± S.D. of three independent experiments performed in triplicate. *, p < 0.005 relative to vector control, calculated using an unpaired Student's t test.