Self-antigen

A self-antigen is a protein or other molecule naturally produced within an organism that the immune system recognizes as 'self,' meaning it should not be targeted for destruction. Under normal circumstances, the immune system tolerates these self-antigens, preventing autoimmune reactions. However, in certain conditions, this tolerance breaks down, leading the immune system to attack the body's own tissues and cells, resulting in autoimmune diseases. Understanding self-antigens is critical in immunology, particularly in the study of autoimmune disorders and immune tolerance.

Self-antigen meaning with examples

• In individuals without autoimmune conditions, T cells typically ignore self-antigens. This is crucial for maintaining immune homeostasis. If self-antigens were erroneously targeted, the resulting immune response could lead to the destruction of vital organs and tissues. The immune system is trained to distinguish self from non-self during development.
• Autoimmune diseases often involve the immune system's failure to recognize self-antigens. In conditions like rheumatoid arthritis, the body attacks self-antigens present in the joints, causing inflammation and pain. Similarly, in lupus, the body attacks self-antigens found in various tissues and organs.
• Researchers are developing therapies aimed at re-establishing immune tolerance to self-antigens. These therapies seek to reprogram the immune system, preventing it from attacking the body's own molecules. This approach is particularly relevant in the treatment of autoimmune diseases, such as type 1 diabetes, which targets self-antigens in the pancreas.
• During development, the immune system undergoes a process of 'negative selection,' where T cells that strongly react to self-antigens are eliminated or suppressed. This mechanism helps prevent autoimmune responses. If negative selection fails, self-reactive T cells can escape and cause damage.