|Polyclonal antibody production||Monoclonal antibody production|
|Recognization||Multiple epitopes||Single epitope|
|Specificity||Improved specificity after antigen affinity purification||High|
Protein A and protein G are bacterial proteins with well-characterized antibody-binding properties. They are covalently immobilized onto porous resins and bind to most species and subclasses of IgG.
In order to remove non-specific staining and increase signal strength in WB analysis, affinity purification against the antigen is considered as a priority of polyclonal antibody production. The particular antigen used for immunization is immobilized to specifically bind to target antibody in the process of purification.
Recombinant protein and polypeptides with MW larger than 9kDa are generally considered as priorities when the goal is to produce multiple custom antibodies and detect multiple epitopes on the target antigen. The purified antibodies possess broad available affinity and utility for downstream applications. Compared with peptide antigen, it is more likely to generate certain custom antibodies that bind to epitopes on antigen surfaces if start from recombinant protein with proper folding and structures.
Based on knowledge of target protein and previous researches, peptides with specific epitopes are conjugated with immunogenic carrier proteins (KLH, BSA, etc.) to produce custom antibodies against point mutations and post-translational modifications (phospho-specific antibody production).