Antigen sequestration

Definition

Antigen sequestration refers to the process by which certain antigens are hidden or kept away from the immune system, preventing an immune response against them. This mechanism is crucial for maintaining immune tolerance, especially for self-antigens that could potentially trigger autoimmune reactions. By sequestering these antigens in specific tissues or organs, the body can reduce the risk of unwanted immune activation while still allowing for normal physiological functions.

5 Must Know Facts For Your Next Test

1. Antigen sequestration is especially important for antigens found in immune-privileged sites, such as the brain, eyes, and testes, where exposure to the immune system could lead to harmful inflammatory responses.
2. This process helps prevent autoimmune diseases by reducing the likelihood of self-reactive T and B cells from encountering their specific antigens.
3. Sequestration can occur through physical barriers like blood-brain barriers or through the expression of regulatory proteins that inhibit immune cell activation.
4. In some cases, antigen sequestration can be reversed if there is tissue damage or inflammation, allowing previously hidden antigens to become accessible to the immune system.
5. Research is ongoing into how manipulating antigen sequestration could be used therapeutically to treat autoimmune diseases or enhance tolerance in transplant patients.

Review Questions

• How does antigen sequestration contribute to maintaining immune tolerance?
  • Antigen sequestration contributes to maintaining immune tolerance by keeping specific antigens out of reach from immune cells, particularly self-antigens that could trigger an autoimmune response. By sequestering these antigens in certain tissues or organs, the body minimizes the chances of self-reactive lymphocytes encountering their targets and becoming activated. This process is essential for preventing unwanted immune reactions that can lead to tissue damage.
• Discuss the role of antigen sequestration in autoimmune disease prevention and how it interacts with central and peripheral tolerance mechanisms.
  • Antigen sequestration plays a key role in preventing autoimmune diseases by limiting exposure of self-antigens to immune cells. Central tolerance mechanisms eliminate or inactivate self-reactive lymphocytes during development, while peripheral tolerance ensures that any remaining self-reactive cells do not become activated in tissues. Sequestration acts as an additional layer of protection; by keeping antigens hidden, it reduces the likelihood that even those lymphocytes that escape central tolerance will provoke an autoimmune response.
• Evaluate the potential implications of targeting antigen sequestration for therapeutic interventions in autoimmune diseases.
  • Targeting antigen sequestration for therapeutic interventions could have significant implications for treating autoimmune diseases. By enhancing the ability to sequester self-antigens, it might be possible to prevent self-reactive immune cells from becoming activated and attacking healthy tissues. Alternatively, selectively modulating sequestration could promote tolerance in transplant patients by reducing graft rejection. However, careful consideration must be given to avoid unintended consequences such as increased susceptibility to infections or malignancies due to weakened immune surveillance.

Related terms

Central tolerance: A mechanism that occurs during immune cell development, where immature T and B cells that react against self-antigens are eliminated or rendered non-functional.

Peripheral tolerance:

A set of mechanisms that operate after immune cells have matured, aimed at preventing activation of self-reactive cells in the peripheral tissues.

Autoimmunity:

A condition in which the immune system mistakenly attacks the body's own tissues, often due to a breakdown in tolerance mechanisms.