SdrF-mediated binding to keratins 1 and 10. The binding of Lactococcus lactis surface-expressed SdrF (SdrF on x-axis) and the ligand-binding domains A and B was compared with L. lactis containing the control vector pOri23 (pOri23). Pan-cytokeratin antibody (1 µg/mL) was used in inhibition assays (anti-K). A, Binding of full-length SdrF and the A and B domains to keratin 1. B, Binding to keratin 10. Full-length SdrF, as well as ligand-binding domains A and B, bind keratins 1 and 10. Antibodies directed against SdrF and the A and B domains significantly reduced binding. Data represent the number of bacterial colony counts per well and represent means and standard errors from ≥3 experiments (3 microtiter wells per experiment) for the binding studies and 2 experiments (3 microtiter wells per experiment) for the antibody inhibition assays.