Western blot analysis of antiserum induced by phagotopes. Two phage (clones D1 and H1) were used to immunise BALB/c mice through intraperitoneal administration. For each immunisation, 1012 pfu phage (in 50 μl) was used, with TBS and wild-type M13 phage as controls. Three mice were immunised with each sample and pre-immune sera were obtained. The mice were bled once (pre-booster), and they were given a booster in the same manner. The immune mice were bled every 7 days after booster immunisation, and western blotting was performed to test each serum sample. 1: serum from D1 phagotope; 2: serum from H1 phagotope; 3: pre-immune serum; 4: serum from wild M13phage; 5: serum from TBS.