Figure 15.

Detection of the CEA protein by using AP-α-CEA-λ phage. Four 1 μl drops containing the indicated amount of the purified CEA or irrelevant GST protein were applied onto the marked squares of each nitrocellulose filter. Then the filters were air dried approximately for 5 min and incubated with 10¹⁰ PFU/ml phage solutions for 1 h at RT, washed and developed by using AP chromogenic substrate. Filter A was incubated with the wild type phage λKM4, filter B with the AP-α-CEA-λ phage displaying AP as a fusion to the C-terminus of the gpD and anti-CEA scFv antibody as a fusion to the C-terminal end of the truncated gpV.