When we talk about the immune system and how it starts to work, it's impossible not to mention antigens. However, what are antigens? How are they able to trigger these reactions in our bodies?Next, we will explain what these substances are.
→ How can we define an antigen?
Antigens can be defined as molecules that can bind to antibodies.Many authors prefer to define it as any substance capable of promoting a response by the system immune, however, there are antigenic substances that react with the antibody, but are not able to stimulate its production.
Therefore, we can classify the antigens into two groups:
Immunogens: Immunogens are those antigens that can trigger an immune system response. At this point, it is important to highlight that every immunogen is an antigen, but not every antigen is an immunogen.
haptens: These are molecules that react with antibodies, however, alone, they are not capable of triggering an immune response. To trigger these reactions, the haptens must be coupled to carrier molecules.
→ Some examples of antigens
Antigens are generally unknown molecules in the body. Molecules that detach from foreign cells such as bacteria, fungi, protozoa or even viruses can be considered antigens. Toxins released by bacteria are also examples of substances that can bind to antibodies.
→ What are vaccines?
At vaccines are immunobiologicals that stimulate our immune system to produce antibodies. They are produced from inactive or attenuated antigens, which stimulate the production of antibodies and cells of memory, which makes the body able to quickly identify when that antigen re-enters our body. It is noteworthy that vaccine antigens are inactive or attenuated, therefore, they are incapable of causing serious damage to health.
By Ma. Vanessa Sardinha dos Santos
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/biologia/o-que-e-antigeno.htm
