How does the immune system prevent autoimmunity?

The immune system prevents autoimmunity primarily by suppressing cells that react to self antigens. This mechanism is crucial for maintaining tolerance to the body’s own tissues and avoiding immune responses against self molecules.

Central tolerance is established during the development of T cells and B cells. For T cells, this occurs in the thymus, where developing T cells are exposed to self antigens. Those that strongly react to self antigens are either eliminated through a process known as negative selection or rendered anergic (inactive). Similarly, immature B cells that recognize self antigens can be negatively selected in the bone marrow or undergo receptor editing to change their specificity.

Additionally, regulatory T cells (Tregs) play a vital role in peripheral tolerance. These cells actively suppress the immune response to self-antigens, preventing potentially harmful autoimmune reactions from occurring.

In contrast, enhancing the activity of B-cells, producing more antibodies, or increasing the number of neutrophils could contribute to an inappropriate immune response or heightened inflammation rather than protecting against autoimmunity. Therefore, the immune system relies on suppressing reactive cells to maintain balance and prevent autoimmunity effectively.