Antigenicity and Immunogenicity

Any substance that creates an immune power against it is known as antigenicity of that substance. It includes chemicals, bacteria, toxins, viruses, and many more substances that are coming from foreign or outsides of the body. All body cells and tissues, even cancer cells have antigens to protect them from the outside response. Immunogenicity is a substance that has immune responses for any antigen which is capable of inducing an immune response. Sometimes antigen and immunogenic are used interchangeably with each other. 

This chapter is designed to provide a deep understanding of the concept of Antigenicity and Immunogenicity, the difference between antigen and immunogen with examples. Along with that, it will also cover the importance of antigen and immunogenicity in the human body’s protection against pathogens.  

What are Antigenicity and Immunogenicity?

Immunogenicity is a substance that refers to the ability to induce hormonal and cellular immune systems, whereas antigenicity refers to the ability to recognize the specified antibodies generated as the result of a given substance’s result on immunity. Immunogenetic substances are all antigenic but all antigenic substances are not immunogenetic. 

Factors that affect or determine immunogenicity are listed below

• Foreignness
• Molecule size
• Chemical nature
• Physical form
• Susceptibility to antigen

The antigen must be a foreign substance, with a mass of 14,000 to 600,000 da. They are polysaccharides and protein substances. When the complexity of antigens increases the immunogenicity increases. 

All the antigens are specific in the species. Therefore, immunogenicity is a character that provokes the immune system of the body which can be wanted or unwanted. Wanted immunogenicity related to the vaccine, where a body got injected with antigen and it provokes the immune system against the pathogens from future exposure. The unwanted antigen can be known as immunogenicity by an organism against normal antigen. 

What is the difference between antigen and immunogen? 

The biggest difference between antigen and immunogen is that antigens bind the structure of components related to the immune system including antibodies and B and T cells. On the other hand, immunogens are antigen that induce the immune response. 

Antigens are molecules that bind the immune system, and they generally include antibodies and t and B ties cells. 

Antigens are made of protein, polysaccharides, lipids, peptides, or nucleic acids. An antigen can contain one or more than one epitopes or determinants of an antigen. The complementary part of epitopes is called paratopes. 

There are four types of antigens, 

• Exogenous antigens
• Autoantigens 
• Endogenous antigens
• Neoantigens 

Immunogen is a type of antigen that provokes the immune system. All immunogens are antigens, but not all antigens are immunic in structure. Basically, they are made of large polysaccharides, peptides, and proteins. Immunogens can either trigger cell-mediated or hormonal immune systems and responses. 

There are also some similarities between these two, such as

• Both are present in pathogenic microorganisms, or cellular surfaces of the foreign bodies
• Both work to mark the antibodies to produce and provoke
• The composition of both immunes is protein, glycoproteins, lipids. 
• Through different chemical linkages, both have the ability to bind antibodies. 
• Both natures are antigenic 
• Both are useable under the molecular diagnosis and Vitro condition 

What is the antigen and immunogen example?

Antigenicity and immunogenicity biology provide that, allergens, HLA, foreign cells substances on the surface, toxins, blood group antigens, etc are examples of antigens. 

The best example of an immunogen is a hapten. Haptens are molecules of low weight that can be bound by an antibody but cannot elicit any immune response.

What is the importance of Antigenicity and Immunogenicity?

Antigenicity is important as it is a part of the immune response. They help a body to identify and recognize harmful threats and help to get rid of them. Antibodies are the cells created between the immune system, and they promote the pathogens to get eliminated from the body. it also distributes the thread among the other parts of the body to provoke the immune system. 

Immunogenicity is also the same in work to protect and provoke the immune structure and response to fight against pathogens and foreign molecules. It also helps to strengthen the magnitude of the immune system. 

Conclusion

Antigens and antibodies often become confused while discussing their nature. But they hold a very prominent place when it comes to protecting the body by provoking the immune system within the body. Antigens act as an antibody generator and along with infectious diseases, it also gets eliminated from the body. But antigens are not the main attraction in body immunity but it plays an important role in eliminating and preventing infectious disease from the body that can be harmful. 

This chapter has covered the basic idea of Antigenicity and Immunogenicity and also covered the differences between antigen and immunogen. This will provide a detailed concept of the immune system ad how does the immune system work in order to fight again pathogens to protect our body.