Anti-Tcd169, anti-mTcd138 and anti-Tcd169FI sera cross-reacts with C. difficile surface proteins. Immune sera were collected after 3rd immunizations (i.p.) of mice with 10 μg of Tcd169, mTcd138 or Tcd169FI in the presence of alum in this work or previously Across reactivities of anti-Tcd169, anti-mTcd138 and anti-Tcd211 sera with C. difficile surface proteins FliCD (A), SlpA (B), and Cwp2 (C) were determined by ELISAs (*, P < 0.05 and **, P < 0.01 versus preimmune sera).