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Polyclonal and monoclonal antibodies differ greatly in their production and their uses. This article outlines the key differences, advantages and disadvantages of polyclonal and monoclonal antibodies.

Polyclonal Antibodies

Polyclonal antibodies are created by injecting a host with an immunogenic substance. The immunogenic substance causes an immune response in the host, and results in the activation of multiple B-cells which all target a specific epitope on the immunogenic substance. This results in the production of a large number of antibodies, with varying paratypes, which target different sites on the antigen. The polyclonal antibodies created can then be used straight from the serum or they can be purified, in order to remove the other serum proteins present. Polyclonal antibodies display high batch-to-batch variability as new hosts are required to create the next batch.

Monoclonal Antibodies

Monoclonal antibodies are created by injecting a host with an immunogenic substance. After the immunogenic substance has created an immune response within the host, B-cells are extracted from the spleen and fused with myeloma cells to create immortal, hybridoma cell lines. Single B-cells are fused and cultured into their own hybridomas, creating a culture of B-cells all producing the same specific, monoclonal antibody. Every hybridoma is assigned a specific clone number in order to identify the particular monoclonal antibody and the specific epitope it binds to. Monoclonal antibodies are excreted by the B-cells into the culture media where they can be extracted for validation and purification. Once a hybridoma cell line has been produced, it is a stable and renewable source of monoclonal antibodies with each batch identical to the previous. Hybridomas can also be injected into the peritoneal cavity in mice to create a tumour that secrets a fluid high in antibodies, known as ascites fluid.

Summary

Polyclonal or Monoclonal Antibodies?

Polyclonal antibodies recognise multiple epitopes on any one antigen with this capability providing several advantages:

  • It can increase the signal produced by a target protein, as the antibodies bind to more than one epitope.
  • They are less sensitive to antigen changes (i.e. polymorphism, slight denaturation, etc.) compared to monoclonal antibodies.
  • They are useful when the nature of the antigen is unknown.
  • They provide more robust detection, due to binding to more than one epitope.

Monoclonal antibodies recognise one specific epitope on any one antigen, which provides several advantages:

  • They are more specific than polyclonal antibodies, which decreases background noise and reduces cross-reactivity.
  • All batches produced are identical, which helps provide reproducible results between experiments.
  • High specificity makes monoclonal antibodies extremely efficient at binding to an antigen within a mixture of related molecules (i.e. during affinity purification).

Before deciding upon a polyclonal or monoclonal antibody for your research, you will need to consider the advantages and disadvantages of both in the context of your planned applications.

If you require assistance in deciding which antibodies are most suitable for your work please contact us - we are more than happy to assist you!