Antibodies are the large proteins having a Y-shape known as immunoglobulins that the B-cells produce as a portion of the immune and adaptive response at the time of meeting a foreign molecule. Because of the antibody’s powerful affinity to a specific sequence (epitope), you can use them in research to locate and point out exact proteins of interest from different applications.
Two main kinds of antibodies are present to scientists for answering different research needs: polyclonal and monoclonal antibodies. Here are the top five differences between monoclonal and polyclonal antibodies.
1. The Definition of Monoclonal and Polyclonal Antibodies
One or monotype of antibody attaches to a particular epitope on the antigen it targets to make up monoclonal antibodies. On the other hand, many (poly) different antibodies binding to many different epitopes on the target antigen create the polyclonal antibodies.
2. The Production of Monoclonal and Polyclonal Antibodies
The main difference in the custom antibody lies in the production process:
Monoclonal Antibody:
Experts give an immunogen first to a host animal to create monoclonal antibodies. After the immunogen causes an immune response, you will extract the B-cells from the spleen and fuse them with cancer B-cells (myeloma cells). Perfect spleen cells do not last indefinitely in the cell culture. So, the fusing process gets used for making an immortal cell line. This process helps to create a hybridoma cell line.
The mono-culture of B-cells, all creating the same antibody, get created by culturing and fusing single B-cells from the spleen in their hybridomas. Each hybridoma gets a particular clone number to produce a specific monoclonal antibody such that the specific epitope and particular antibody that it binds get identified. The cell culture media gets the monoclonal antibodies secreted by the B-cells. Now, you can extract them for experimentation and purification.
Creating a monoclonal antibody hybridoma clone offers a renewable and excellent antibody resource, ensuring that every batch is the same as the earlier one. Hybridomas might also get injected into the mouse’s peritoneal cavity to create a tumor secreting a fluid rich in antibodies known as ascites fluid.
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Polyclonal Antibody:
For making polyclonal antibodies, an immunogen gets injected into a host animal. The immunogen activating multiple B-cells causes an immune response in it. All of these factors target a particular epitope on the immunogen. You will get different affinities for the target protein since lots of antibodies with different paratopes come from this.
After immunization, you can use the polyclonal antibodies straight from the serum (i.e., blood with the red blood cells and clotting proteins removed). You can also choose to purify them to get a solution free from any serum protein. Creating a new batch would mean immunizing new animals such that a high amount of variability is present from one batch to another.
3. The Best Possible Uses of Monoclonal and Polyclonal Antibodies
When it comes to the use of both the antibodies, they have a lot of differences which are as follows:
Monoclonal Antibodies:
- Detection of a particular antigen
- Detecting a single member of a protein family
- Creating consistent results between batches/experiments
- Staining cells with less background (ideal for immunofluorescence, immunocytochemistry, and immunohistochemistry experiments)
- Quantifying protein expression (for instance, fluorescence-activated or flow cytometry sorting)
- Detection of changes in molecular conformation
- Detection of changes in phosphorylation states
- Detection of a target for x-ray crystallography
- Creating animal models without having a particular cell type
- Immunotherapy
Polyclonal Antibodies:
- Detection of unknown or known isoforms of antigens with high levels of antigen homology
- Detection of low levels of a specific antigen
- Capturing the maximum levels of antigen (for instance, chromatin immunoprecipitation or immunoprecipitation)
- Detection of denatured proteins
- Detection of targets with probable conformational changes, glycosylation, or genetic polymorphisms
- Detection of native proteins across varied essay types
- Detection of a target in solutions having different salt and pH concentrations
4. Unsuitable Situations for Monoclonal and Polyclonal Antibodies
Both the monoclonal and polyclonal antibodies are not suitable for some situations, which are:
Monoclonal Antibodies:
- Detection of target proteins across various species depending on homology
- Finding out the low levels of target proteins
- Detection of a protein in a changed conformation
Polyclonal Antibodies:
- For instance, quantification experimentation, for example, flow cytometry, as wrong results will enhance the signal because of several binding sites.
- Cases where problems exist with cross-reactivity as well as higher homology proteins
5. The Generation of Monoclonal and Polyclonal Antibodies
Polyclonal Antibodies
Polyclonal antibodies are more rapidly generated and at less expense with less technical skills than what you need to produce monoclonal antibodies.
You can reasonably expect to get polyclonal antibodies within a few months of starting immunizations.
Monoclonal Antibodies
In contrast, the generation of hybridomas and subsequent production of monoclonal antibodies can take at least 10-15 days or even longer in some cases. Thus, it needs more time and costs than polyclonal antibodies. The availability of a reagent does away with the issues of cost and time.
The Bottom Line
For applications like the development of therapeutic drugs that need vast volumes of matching antibodies particular to one epitope, it is best to use monoclonal antibodies. The benefits of polyclonal antibodies outweigh the ones of monoclonal antibodies for general research purposes. You need to keep in mind the differences mentioned above when making a decision.