Do I Need a Monoclonal Antibody?
Monoclonal antibodies are excellent tools in terms of ensuring a long-term, reproducible supply of an epitope-specific antibody. However, for many of our customers’ applications, monospecific antibodies are a more cost-effective solution.
Monoclonal antibodies provide two key advantages – 1) antibodies from the single clone are specific to a single epitope (a unit of 5-7 amino acids against which an individual antibody binds) and 2) large quantities of this identical epitope-specific antibody can be expressed over a long time period. This ability to target a single epitope provides extremely high specificity in terms of targeting the antigen of interest. And, the ability to express large quantities of antibody that are identical from batch to batch is critical for applications such as diagnostic kits and therapeutic drugs.
However, the biggest downside with monoclonal development is the high cost of screening / isolating the clone and then expressing the sequence-defined antibody.
Polyclonal antibodies, by definition, consist of antibodies against multiple epitopes. In the context of a full-length protein, this could lead to less specificity if domains or epitopes within the protein sequence are conserved. However, if we focus on a particular region of the protein and immunize with a small peptide (15-20 amino acids for example) corresponding to that region, then we end up with a very small pool of antibodies recognizing multiple epitopes within that peptide sequence. However, this ability to recognize multiple epitopes (compared to a monoclonal antibody that can only recognize a single epitope) in a targeted region provides superior affinity, quicker binding capability and more robustness in the event that denaturation, polymorphisms or conformational changes occur.
Next, by affinity purifying serum against the peptide sequence, we can isolate this small pool of antibodies against epitopes on the peptide sequence and thereby approach the specificity of a single monoclonal antibody. These highly specific polyclonal antibodies are typically known as monospecific antibodies and represent one of the most popular services that we offer. In addition, these antibodies can be produced quicker and for a fraction of the cost of a typical monoclonal project.