Detection of the binding activity of representative phage clones with four Ig molecules respectively by ELISA (A-D). Each of Ig molecules (labeled on top of each graph) was coated on ELISA plates using 0.1 M NaHCO3 (pH 9.6). The amplified representative phages (2 × 1011 TU) were added to each well and Ig-bound phages were detected with horseradish peroxidase (HRP)-conjugated anti-M13 antibody. The displayed sequence of each representative phages was: 1, PA(A)3N-PG-PA(A); 2, PA(A)6N-PG; 3, PA(A)-PG; 4, PA(A)-PG9N; 5, PA(A)6N-PG3N; 6, PA(A)9N-PL3N; 7, PA(A)-PL-PL9N; 8, PA(A)9N-PL; 9, SpA-phage (positive control); 10, 2L-phage (positive control); 11, pCANTAB5S-phage (negative control). Comparable data were obtained in three independent experiments.