L22 - Immunological Tolerance

Question 1

low zone tolerance

Answer 1

• tolerance mechanism in which immune system becomes desensitized to an antigen that is present in only small amount
• causes peripheral T-cell selection due to lack of secondary signaling

Question 2

high zone tolerance

Answer 2

• form of immune tolerance in which the immune system does not react against an antigen present in large quantity
• causes B-cell anergy due to excessive cross-linking

Question 3

anergy

Answer 3

inactive, quiesent state that self-reacting lymphocytes may enter if they escape negative selection

Question 4

follicular exclusion

Answer 4

process by which anergic B-cells are excluded from follicles; this would explain why immunodeficient patients also often have autoimmune diseases; they do not have cells that compete in the follicles, allowing the anergic cells to become activated

Question 5

receptor editing

Answer 5

process by which autoreactive B-cells can undergo further editing

Question 6

clonal ignorance

Answer 6

observation that the immune system is ignorant to antigens that it does not encounter (i.e., antigens in closed organs)

Question 7

Treg cells

Answer 7

• induced by Foxp3 or TGF-B
• secrete IL-10 and TGF-B

Question 8

type I reaction

Answer 8

1. caused by IgE
2. soluble antigen
3. activated by mast cells

Question 9

type II reaction

Answer 9

1. IgG
2. cell or matrix associated antigen
3. activated by FcR cells (phagocytes and NK cells)

Question 10

type III reaction

Answer 10

• IgG
• soluble antigen
• activated by FcR cells, complement

Question 11

type IV reaction

Answer 11

hypersensitivity reaction caused by T-cells

Question 12

sympathetic opthalmia

Answer 12

disease in which trauma to one eye can lead to an immune attack against the other, uninjured eye

Question 13

Goodpasture’s disease

Answer 13

type II immune response against collagen IV, resulting in kidney failure

Question 14

IPEX

Answer 14

• immune dysfunction, polyendocrinopathy, enteropathy, X-linked
• genetic condition characterized by a lack of CD25 T-reg cells

Question 15

inactive, quiesent state that self-reacting lymphocytes may enter if they escape negative selection

Answer 15

anergy

Question 16

process by which autoreactive B-cells can undergo further editing

Answer 16

receptor editing

Question 17

observation that the immune system is ignorant to antigens that it does not encounter (i.e., antigens in closed organs)

Answer 17

clonal ignorance

Question 18

1. caused by IgE
2. soluble antigen
3. activated by mast cells

Answer 18

type I reaction

Question 19

1. IgG
2. cell or matrix associated antigen
3. activated by FcR cells (phagocytes and NK cells)

Answer 19

type II reaction

Question 20

• IgG
• soluble antigen
• activated by FcR cells, complement

Answer 20

type III reaction

Question 21

hypersensitivity reaction caused by T-cells

Answer 21

type IV reaction

Question 22

disease in which trauma to one eye can lead to an immune attack against the other, uninjured eye

Answer 22

sympathetic opthalmia

Question 23

type II immune response against collagen IV, resulting in kidney failure

Answer 23

Goodpasture’s disease

Question 24

• immune dysfunction, polyendocrinopathy, enteropathy, X-linked
• genetic condition characterized by a lack of CD25 T-reg cells

Answer 24

IPEX