Definition of Antigens



Antigens are substances that have the ability to stimulate an immune response in the organism’s body. They specifically activate the white blood cells like lymphocytes which fight the infections that have occurred in a body. There are main two types of antigens i.e. foreign antigens and autoantigens. The foreign antigens are also known as heteroantigens and they enter the organism’s body from the surrounding environment. On the other hand, the autoantigens are originated within the body.

 


In normal cases, the body is capable to differentiate between the autoantigens and foreign antigens but the organisms who suffer from autoimmune disorders cannot. The antigens which stimulate the white blood cells to produce an antibody are known as immunogens.

 


Examples of Antigen:

Examples of antigens include the substances that are produced by viruses and other microorganisms, snake venom, serum, the blood of other individuals, etc.


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