Regulation of Adaptive Immunity

Question 1

Tolerance

Answer 1

the ability of the immune system to ignore certain peptides that have the potential to trigger an immune response

Question 2

Self-tolerance

Answer 2

the ability of the immune system to ignore self-peptides that have the potential to trigger an immune response.

Question 3

Autoimmune Disease

Answer 3

breakdown in self tolerance

Question 4

Allergies

Answer 4

breakdown in tolerance to environmental antigens (food, pollen)

Question 5

Central Tolerance

Answer 5

the induction of tolerance during lymphocyte development in primary lymphoid organs

Question 6

Peripheral Tolerance

Answer 6

the regulation of autoreactive T and B lymphocytes that can recognize self antigens in the circulation and in peripheral tissue

Question 7

Central Tolerance of T Lymphocytes

Answer 7

1. Achieved through negative selection. T cells in the thymus are eliminated if they are self-reactive
2. Some self-reactive T cells develop into regulatory T cells instead of being eliminated

Question 8

What is Treg

Answer 8

CD4

Question 9

Central Tolerance of B Lymphocytes

Answer 9

1. achieved through negative selection. B cells in the bone marrow are eliminated if they are self-reactive
2. When BCR on an immature B cell recognizes self-antigen, receptor editing occurs during which immunoglobulin light chain rearrangements continue in order to change the BCR specificity

Question 10

Peripheral Tolerance Process

Answer 10

1. Lack of the costimulation required for T cell activation: costimulatory molecules such as CD40 or CD28 are found on APCs but not on other body tissues
2. Tregs secrete IL-10 and TGF beta in the presence of autoantigen reactive T cells. These cytokines suppress surrounding T cells

Question 11

Peripheral Tolerance Basic Process

Answer 11

1. Anergy or
2. Suppression or
3. Deletion

Question 12

Anergy

Answer 12

cell becomes non-responsive

Question 13

Suppression

Answer 13

block in activation

Question 14

Deletion

Answer 14

apoptosis

Question 15

Clonal Anergy

Answer 15

triggered when T cells are exposed to antigens in the absence of effective co-stimulation

Question 16

Function of Inhibitory Receptors

Answer 16

ensure inactivated cells remain inactive

Question 17

Tregs

Answer 17

FOXP3, CD4, and CD25

Question 18

TGF beta

Answer 18

inhibits the proliferation and effector functions of T cells and the activation of macrophages. Promotes tissue repair after local immune and inflammatory reactions subside

Question 19

IL-10

Answer 19

Inhibits the production of IL-12 by activated DCs and macrophages. IL-10 inhibits the expression of costimulators and class II MHC molecules on Dcs and macrophages

Question 20

Why are B cells harder to tolerize than T cells?

Answer 20

1. because there is no single location in which affinity maturation takes place. During affinity maturation B cells hypermutate to produce high affinity antibodies, so even though parent B cells were tolerant to self, they can clone daughter B cells that produce self-reactive antibodies
2. Affinity maturation takes place in lymph nodes, of which there are many distributed throughout the body
   3.

Question 21

Suppressive cytokines produced by Tregs

Answer 21

TGF beta and IL-10

Question 22

CD4 Th Cells recognize what?

Answer 22

exogenous peptide bound to MHCII