Monoclonal vs. Polyclonal Antibodies: Which is Better for Your Project?

Monoclonal and polyclonal antibodies present their own advantages and drawbacks. Understanding which one is right for you involves understanding how the antibody will be used. Specifically, the required sensitivity, specificity, and experimental reproducibility between batches are several ways monoclonal and polyclonal antibodies differ. These variables relevant to the intended application of the antibody need to be carefully evaluated before choosing the appropriate antibody type.

Production time and budget can also influence one’s choice. These criteria, therefore, imply having a long-term vision of your project and the antibody technologies you will use. To help you make the right decision (and because you might not have the time to read the entire article), we developed a free tool that helps you choose which antibody type is right for you.

Our quiz can help you choose between a polyclonal and monoclonal custom antibody and also choose the most appropriate monoclonal antibody production method – hybridoma development or antibody phage display. Try it by clicking on the button below!

 

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A Dive into Polyclonal Antibodies

Polyclonal antibodies (pAbs) are a heterogeneous mixture of antibodies that bind varying locations of the immunized antigen. Each immune response from the immunized animal produces a slightly different cocktail of antibodies that bind the target antigen. 

This can pose antibody variability challenges when your custom polyclonal antibody is depleted, and it becomes necessary to make a new batch (batch-to-batch variability). Polyclonal antibody production provides a variety of heterogeneous antibodies that bind several epitopes (regions) of the same target molecule (antigen).

This antibody heterogeneity and broad epitope recognition are particularly useful for detection-based methods in specific research experiments, such as for detecting antigens of low abundance in a complex mixture, unfolded (denatured) proteins, or antigens that have variable chemical modifications (post-translational modifications) that might prevent antibody binding of a single, modified, epitope.

What Are the Disadvantages of Polyclonals?

In general, polyclonal antibodies have decreased antigen specificity compared to monoclonal antibodies. This means that some antibodies in the polyclonal antibody mixture could cross-react with epitopes from other antigens that have a similar charge and structure. This increases the ‘background noise,’ making polyclonal antibodies inappropriate for clinical applications.

Nonspecific antigen binding can be reduced by immunizing animals with smaller parts of the antigen, such as polypeptide segments of the full antigen. This limits the antibody recognition of an antigen to one or a few specific epitopes.

What are the Benefits of Polyclonal Antibodies?

Polyclonal antibody production is a fast and affordable process, which constitutes a significant advantage over monoclonal antibody production. It can be used for many research applications that do not require a high specificity or a standardized process, as well as for diagnostic assays. 

In the case of the ELISA sandwich, pAbs can also be used together with mAbs. The latter bring specificity, while the pAbs help improve the affinity and make possible the binding with epitopes that remain accessible once captured by the monoclonal antibody.

Affinity purification can also help selectively remove nonspecific antibodies from the ultimate polyclonal assembly, rendering it suitable for detection-centric techniques such as Western blotting, immunohistochemistry, immunofluorescence, and enzyme-linked immunosorbent assays (ELISA).

Understanding Monoclonal Antibodies

Monoclonal antibodies (mAbs) are a homogeneous mixture of antibodies that bind one location (epitope) of a target molecule. These antibodies are derived from a single B cell and must, therefore, be isolated from an animal to obtain a pure source of identical antibodies. The monoclonal (and polyclonal) antibody structure consists of four polypeptide chains arranged in a Y-shaped unit. 

Each Y unit contains two identical copies of a heavy chain (H) and two identical copies of a light chain (L). The top of the ‘Y shape’ is called the fragment antigen-binding region (Fab region) due to the presence of four variable regions (V) that bind an epitope, two variable regions on each heavy chain (VH), and two variable regions on each light chain (VL).

What Are the Benefits of Monoclonal Antibodies?

In contrast to polyclonal antibodies, B cells must be isolated from animals before a custom monoclonal can be produced antibody selection and isolation can be done based on their specificity and sensitivity features. If the DNA sequence of the monoclonal antibody is known, then scientists can genetically engineer smaller versions (formats) of the antibody that retain antigen-binding potential. They can also make unique full-length antibodies that bind two different antigen targets at once, termed bispecific antibodies.

Therapeutic Benefits of Monoclonal Antibodies

Given that monoclonal antibodies are derived from a single genetic code, they can be manufactured at scale to make large batches of identical antigen-specific antibodies. For these reasons, in addition to their minimal cross-reactivity, monoclonal antibodies are the only antibody type used in therapeutic antibody development.

The ability to genetically manipulate monoclonal antibodies has become particularly impactful in the realm of:

1. Cancer

•       Breast cancer (e.g., Trastuzumab for HER2-positive breast cancer)
•       Colorectal cancer (e.g., Bevacizumab)
•       Leukemia (e.g., Rituximab for non-Hodgkin lymphoma)
•       Lymphoma (e.g., Brentuximab vedotin)

2. Autoimmune Diseases

•       Rheumatoid arthritis (e.g., Adalimumab, Infliximab)
•       Psoriasis (e.g., Ustekinumab)
•       Crohn’s disease (e.g., Vedolizumab)

3. Inflammatory Diseases

•       Asthma (e.g., Omalizumab)
•       Chronic obstructive pulmonary disease (e.g., Roflumilast)

4. Infectious Diseases

•       COVID-19 (e.g., Casirivimab and Imdevimab, Bamlanivimab and Etesevimab)
•       HIV (e.g., Ibalizumab)
•       Ebola virus (e.g., ZMapp)

5. Cardiovascular Diseases

•       High cholesterol (e.g., Alirocumab, Evolocumab)

6. Ophthalmic Diseases

•       Age-related macular degeneration (e.g., Ranibizumab)
•       Diabetic macular edema (e.g., Aflibercept)

7.  Neurological Diseases

•       Multiple sclerosis (e.g., Natalizumab)
•       Migraine (e.g., Erenumab)

8. Transplant Rejection Prevention

•       Kidney transplant rejection (e.g., Basiliximab)

As mAbs only bind one epitope of the same antigen, tests using monoclonal antibodies result in a lower sensitivity in detecting antigens than polyclonal antibodies. However, their high specificity is a double-edged sword.

Which Is Better, Polyclonal or Monoclonal Antibody? Pros and Cons of Each Antibody Type

The following table offers a concise overview of the advantages and disadvantages of polyclonal vs. monoclonal antibodies to assist you in making informed decisions regarding their utilization in various applications.

By identifying the strengths and weaknesses of each antibody type, this table serves as a valuable tool for researchers, clinicians, and professionals navigating the intricacies of antibody-based methodologies.

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	Polyclonal antibodies	Monoclonal antibodies
Advantages	High sensitivity to an antigen Quickly produced and affordable process The production requires high technical skills The antibodies can recognize several epitopes on the same antigen Small epitope changes shouldn’t impact specificity Not much affected by pH or temperature variations	High specificity High purity Can be quickly produced (Phage Display) High concentrations Unlimited quantities of antibodies can theoretically be produced Lower risk of cross-reactions Can be genetically engineered
Drawbacks	Lower specificity Antigen cross-reactivity likely Lower purity Strong cross-reactivity across specie Animal immunization required Batch-to-batch variability	More expensive to produce Requires advanced technical skills Not optimal for when rapid capture of the target protein is necessary Higher sensitivity to epitope masking from pH changes, post-translational modifications, etc.
Applications	Research applications: Western blot, immunostaining, ELISA Clinical use of anti-toxins, anti-venoms, IVIg therapy, convalescent plasma, etc.	Immunotherapy development (targeted therapies including antibodies for cancer therapy, autoimmune disease treatment, etc.) Research (including flow cytometry, ELISA, Immunoprecipitation, etc.) Clinical diagnostics (rapid antigen tests, ELISA) and clinical imaging techniques

Tips for Choosing Between Polyclonal vs. Monoclonal Antibodies

When deciding between polyclonal vs. monoclonal antibodies for your project, consider asking yourself the following questions:

• Specificity and Epitope Recognition: Choose monoclonals when you need high specificity and precise targeting to ensure consistent results and for applications where cross-reactivity with similar antigens is undesirable. Opt for polyclonal antibodies when broader epitope recognition is beneficial, and the possibility of minimal antigen cross-reactivity can be tolerated, such in western blotting or assays using purified antigens.
• Application and Project Type: Monoclonal antibodies are best suited for quantitative assays (e.g., ELISA, flow cytometry), targeted therapies (e.g., cancer treatment), and precise detection in immunohistochemistry (IHC) and Western blots. Polyclonal antibodies are useful for specific qualitative assays (e.g., screening, diagnostic kits), immunoprecipitation (IP), and initial protein expression screening.
• Budget and Resources: Monoclonal antibodies are more expensive to develop due to complex processes and require specialized facilities. Polyclonal antibodies are cheaper and quicker to produce and can be generated using standard immunization protocols.
• Project Goals and Timeline: If precision and long-term consistency are critical, invest in monoclonal. When speed, lower costs, and broader detection matter, choose polyclonal for time-sensitive projects.

Monoclonal or Polyclonal Antibodies? Choose Wisely

The debate between monoclonal and polyclonal antibodies boils down to understanding the specific requirements of your research or project.  By weighing the pros and cons outlined in this discussion, you should be able to make informed decisions tailored to your goals.

At ProteoGenix, we understand the significance of this decision-making process and are committed to providing comprehensive support every step of the way. Whether your project demands the precision of monoclonal antibodies or the adaptability of polyclonal antibodies, we offer a range of cutting-edge methods to meet your needs. Our team of experts can also assist you in selecting the most suitable antibody approach for your project.

To explore how ProteoGenix can enhance your research with custom antibody solutions or to receive guidance in choosing the right antibody type for your project, don’t hesitate to reach out to us. Let’s advance your research with confidence and precision.