The main difference between antigenicity and immunogenicity is that antigenicity is the ability of a particular substance to be recognized by antibodies produced as a result of a specific immune response. In contrast, immunogenicity is the ability of a substance to induce an immune response that is either cellular or humoral.
Antigenicity and immunogenicity are two reactions that occur in antigens and immunogens, respectively.
Key Areas Covered
1. What is Antigenicity
– Definition, Features, Importance
2. What is Immunogenicity
– Definition, Features, Importance
3. Similarities Between Antigenicity and Immunogenicity
– Outline of Common Features
4. Difference Between Antigenicity and Immunogenicity
– Comparison of Key Differences
Key Terms
Antigenicity, Immunogenicity
What is Antigenicity
Antigenicity is the ability of a particular substance to combine specifically with the final products of the immune reaction, such as secreted antibodies and surface receptors on T cells. Also, the substances that have antigenicity are antigens that can be either proteins, lipids, polysaccharides, or nucleic acids. A particular antigen may contain more than one epitope or antigen determinant. Therefore, epitopes are parts of an antigen. Additionally, four types of antigens can occur in the body. They are exogenous antigens, endogenous antigens, autoantigens, and neoantigens.
Figure 1: Antigenicity
Furthermore, exogenous antigens are foreign antigens from parasites, bacteria, viruses, fungi, and pollen. They are non-self-antigens. Endogenous antigens are the antigens that occur inside the cell during metabolism. In contrast, they are self-antigens. Meanwhile, autoantigens are self-antigens mistakenly recognized as non-self. However, neoantigens are the antigens expressed on the surface of the infected cells.
What is Immunogenicity
Immunogenicity is the ability of a specific substance to generate an immune response that is either humoral or cellular. Immunogenic antigens have this characteristic, which can be either large polysaccharides or proteins. After binding to proteins and large polysaccharides, lipids and nucleic acids can also serve as immunogens. However, immunogens should be complete antigens with epitopes carried by a macromolecular carrier molecule. For example, the hapten is a small molecule that can bind to antigens. But it is unable to generate an immune response. The hapten-carrier complex can induce an immune response when it binds to a nonimmunogenic carrier.
Figure 2: Immunogenicity of Heptan
Moreover, immunogenicity is a crucial aspect of the development of vaccines. There, the injected antigen provokes an immune response against the pathogen. It protects the human body from further infection by a particular pathogen. Significantly, this is called wanted immunogenicity. In contrast, unwanted immunogenicity generates immune responses against therapeutic antigens. It produces anti-drug antibodies (ADAs) that inactivate therapeutic effects.
Similarities Between Antigenicity and Immunogenicity
- Antigenicity and immunogenicity are reactions against antigens and immunogens, respectively.
- They can be either proteins, lipids, nucleic acids, or polysaccharides.
Difference Between Antigenicity and Immunogenicity
Definition
Antigenicity refers to the ability of a specific substance to induce an immunological response when the human body encounters it. In contrast, immunogenicity refers to the ability of a particular foreign substance, such as an antigen, to generate an immune response in the body of a human or other animal.
Substance
Antigens produce antigenicity, while immunogens produce immunogenicity.
Type of Molecules
Lipids, polysaccharides, nucleic acids, and proteins induce antigenicity, while large polysaccharides and proteins induce immunogenicity.
Conclusion
In brief, antigenicity and immunogenicity are two immune reactions that can be induced by antigens and immunogens, respectively. Antigenicity is the ability of a particular substance to be recognized by antibodies to generate a specific immune reaction. Antigens can be either lipids, polysaccharides, nucleic acids, or proteins. In comparison, immunogenicity is the ability of a particular substance to induce an immune reaction. These substances are immunogens that can be either large polysaccharides or proteins. Therefore, the main difference between antigenicity and immunogenicity is the type of reaction.
References:
- Zhang J, Tao A. Antigenicity, Immunogenicity, Allergenicity. Allergy Bioinformatics. 2015 Nov 3;8:175–86. doi: 10.1007/978-94-017-7444-4_11. PMCID: PMC7123983.
Image Courtesy:
- “Antibody” By Fvasconcellos – Own work (Public Domain) via Commons Wikimedia
- “Hapten” By Vaccinationist – Own Work (CC-BY SA 3.0) via Commons Wikimedia
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