Immunological Tolerance: Key Concepts and Clinical Relevance

Study Notes

Definition and Importance

Immunological tolerance refers to the ability of the immune system to distinguish between self and non-self, and to not respond to the body's own antigens.
Tolerance is crucial for preventing autoimmune diseases, where the immune system attacks the body's own tissues.

Types of Immunological Tolerance

Central tolerance: occurs in the thymus, where immature T cells that recognize self-antigens are eliminated or inactivated.
Peripheral tolerance: occurs in the periphery, where mature T cells that recognize self-antigens are inactivated or regulated.

Mechanisms of Immunological Tolerance

Deletion: tolerance is achieved through the deletion of autoreactive T cells in the thymus.
Anergy: autoreactive T cells are inactivated and unable to respond to self-antigens.
Suppression: regulatory T cells inhibit the activity of autoreactive T cells.
Ignorance: self-antigens are not presented to T cells, preventing an immune response.

Factors Affecting Immunological Tolerance

Genetics: genetic defects can lead to impaired tolerance and increased risk of autoimmune diseases.
Environmental factors: exposure to certain toxins or infections can disrupt tolerance.
Hormonal influences: hormonal changes can affect tolerance, particularly in autoimmune diseases.

Clinical Relevance

Autoimmune diseases: impaired tolerance leads to diseases such as type 1 diabetes, rheumatoid arthritis, and multiple sclerosis.
Transplantation: tolerance is crucial for preventing rejection of transplanted organs.
Cancer: tolerance can prevent the immune system from recognizing and attacking cancer cells.

Description

Test your knowledge of immunological tolerance, including its definition, types, mechanisms, and clinical relevance to autoimmune diseases and transplantation. Learn about central and peripheral tolerance, deletion, anergy, suppression, and ignorance, as well as factors affecting tolerance and its importance in preventing autoimmune diseases.