Nested deletion mutants were tested for binding capacity of anti-rPlpE antibodies from bovine and murine sources. 1, rPlpE; 2, rPlpEΔN28; 3, rPlpEΔC86; 4, rPlpEΔC96; 5, rPlpEΔC106; 6, rPlpEΔN76; 7, rPlpEΔN150. (A) Anti-PlpE bovine hyperimmune serum; (B) anti-His-tagged mouse monoclonal antibody; (C) Coomassie stain.