Target Discovery and Validation Reviews and Protocols

Overview of Immune System 305
Fig. 12. Biopanning phage libraries on patient serum antibodies. In this protocol, the
phage library (e.g., peptides and cDNAs) is incubated with patient serum antibodies.
After incubation, biotin-conjugated anti-human IgG antibody was added to capture the
reacting phages. After incubation, reactive phages are captured on streptavidin-coated
magnetic beads, washed, acid eluted, and then amplified in Escherichia coli. Amplified
phages are used for further rounds of selection.
libraries can be used to determine the specificities of antibodies present in
whole sera of patients with breast cancers (75). Homology search with the
selected peptides identified potential tumor antigens. Importantly, patients
who responded to most of the selected peptides exhibited a good prognosis.
The selected antibody ligands can be an important tool for diagnosis, prognosis,
and immunotherapy. In the case of autoimmunity, the characterization of the
autoimmune responses should facilitate the identification of new autoantigens
that may act as tolerizing vaccines.
11.7. Biopanning and Immunoscreening Techniques
The phage display approach is far superior over one-step screening methods
(e.g., SEREX) because sensitivity and selectivity are extremely high when
selecting through iterative, powerful enrichment steps (68). To select phages