What is the Difference Between Self and Non Self Antigens?

The difference between self and non-self antigens lies in their origin and the immune system's response to them.

• Self-antigens are antigens present on the surface of an individual's own cells. They are produced within the body and are not recognized as foreign by the immune system. Examples of self-antigens include autoantigens, which are molecules that the immune system mistakenly identifies as non-self, leading to autoimmune diseases.
• Non-self-antigens are antigens that do not originate in the individual's body. They are found on the surfaces of foreign organisms, such as bacteria, viruses, fungi, parasites, or other non-native biocompounds. The immune system is designed to recognize and respond to non-self antigens by producing antibodies that bind specifically to each antigen.

Immune cells called lymphocytes play a crucial role in distinguishing between self and non-self antigens. They are responsible for producing antibodies that bind to non-self antigens and trigger an immune response. This response can result in neutralizing the pathogenic cell presenting the non-self-antigen or flagging the non-self-antigens to be recognized by other elements of the immune system.

In some cases, the immune system's ability to differentiate between self and non-self antigens can be imperfect, leading to autoimmune diseases or other immune-related disorders. However, the immune system generally maintains a balance between self-tolerance and the ability to recognize and respond to non-self antigens, ensuring the proper functioning of the body's defense mechanisms.

Comparative Table: Self vs Non Self Antigens

Here is a table comparing self and non-self antigens:

Self-antigens are derived from the body itself, and the immune system learns to tolerate them, while non-self-antigens originate from foreign substances and trigger an immune response to neutralize or eliminate the pathogens, chemicals, or toxins carrying these antigens.