Section VII: Tolerance and Autoimmunity

Question 0

When is tolerance to self developed

Answer 0

during fetal development and continues to a lesser degree throughout life

Question 1

What is tolerance

Answer 1

-state of the immune system usually associated with self recognition, the immune system does not respond to self antigens

Question 2

What is central tolerance

Answer 2

Occurs during lymphocyte development

• -T cells: Thymic education
• -B cells: functional cells are selected in bone marrow based on lack of cross-linking antigens

Question 3

What is peripheral tolerance

Answer 3

mechanisms existing to prevent auto-reactivity of lymphocytes after they leave the thymus/bone marrow

Question 4

What is ignorance

Answer 4

T cells and B cells that have the ability to recognize self antigens present in circulation but do because:

• antigen is in to low concentration
• some antigens are sequestered from immune system in locations which are not freely exposed to surveillance

Question 5

What is suppression

Answer 5

a population of T cells exists that prevents other T cells from recognizing self antigens

Question 6

What is Anergy

Answer 6

lack of reaction by the body’s defense mechanisms to antigens

Question 7

What is split tolerance

Answer 7

part of the immune system is tolerant and some other is not

Question 8

What is acquired tolerance

Answer 8

adaptation to external antigens

• pregnancy-tolerance of fetus and placenta
• oral tolerance-the mucosal immune system maintains unresponsiveness to the myriad of antigens
• organ transplantation requires forced tolerance

Question 9

What is autoimmunity

Answer 9

the immune system reacts to self antigens

• usually characterized by the production of autoantibodies
• triggers can vary greatly