Lecture 2.1

Question 1

Unresponsiveness to antigen that is induced by previous exposure to that antigen is called this

Answer 1

tolerance

Question 2

Tolerance is mediated by what type of immunity?

Answer 2

Adaptive immunity

Question 3

At what time period in a human life is tolerance to antigen most easily induced

Answer 3

fetal or neonatal life

Question 4

What type of tolerance stage is located in the thymus and bone marrow and what are the outcomes?

Answer 4

Central tolerance (immature lymphocyte) and three outcomes:

1. Apoptosis
2. B-cell reediting
3. T-reg cells development

Question 5

What type of tolerance stage is located in the peripheral lymphoid tissues and what are the outcomes?

Answer 5

Peripheral tolerance (mature lymphocyte) and three outcomes:

1. Anergy
2. Apoptosis
3. T-reg cell supression

Question 6

What protein can bring peripheral self antigens to the central tolerant areas?

Answer 6

AIRE

Question 7

T-reg cells have what type of cell markers on them and what is the essential cytokine for its activity?

Answer 7

CD25 (IL-2alpha receptor), CD4, Fox3p (mediated by TGF-beta)/ IL-2

Question 8

Long lived state of unresponsiveness to antigenic stimulation

Answer 8

Anergy

Question 9

For T-cells, what are two ways that anergy could occur?

Answer 9

1. No costimulation

2. Antigenic signaling with engagement of inhibitory receptors CTLA 4 (has higher affinity to B7 than CD28) and PD 1

Question 10

What are the substances that T-reg cells secrete or have on them that make them important in tolerance?

Answer 10

IL-10, TGF-beta, CTLA4 expressed on T-reg cells which removes B-7

Question 11

In peripheral T-cell deletion, what are the two outcomes and why does it happen?

Answer 11

Activation induced cell death (AICD) via apoptosis by the mitochondrial pathway or by the FasL extrinsic pathway/ happens because of low or no costimulation

Question 12

Which chain in the B-cell receptor is changed after a strong interaction with self antigen?

Answer 12

Light chain (Rag gene reactivated, must have 2 or more receptors engaged by epitopes so that crosslinking occurs)

Question 13

What causes anergy in B-cells in peripheral tolerance?

Answer 13

Lack of T-helper cell stimulation

Question 14

Which gender is more likely to have an autoimmune disease

Answer 14

females

Question 15

_______ refers to the autoreactivity to a single antigen that can lead to tissue injury and subsequent immune responses to additional antigens

Answer 15

Epitope spreading

Question 16

Genes for what apparatus are the most important genetic factor in autoimmune susceptibility?

Answer 16

MHC

Question 17

MHC Allele affected by ankylosing spondylitis

Answer 17

HLA-B27

Question 18

MHC Allele affected by rheumatoid arthritis

Answer 18

HLA-DR4

Question 19

MHC Allele affected by Type 1 diabetes

Answer 19

HLA-DR3,DR4

Question 20

MHC Allele affected by Pemphigus vulgarius

Answer 20

HLA-DR4

Question 21

What are the two mechanisms of infection induced autoimmunity?

Answer 21

1. Induction of costimulator molecules on APC presenting self-antigens
2. Molecular mimicry

Question 22

What are three dietary substances which can either be deficient or abundant in the diet leads to autoimmunity

Answer 22

Vitamin D (increases T-reg responses, Iodine (thyroglobulin becomes highly iodinated and then immunogenic), Gluten (celiac disease)

Question 23

What are four immune privileged sites in the body?

Answer 23

Brain, eye, testes, fetus/placenta

Question 24

What is the difference between privileged and tolerant?

Answer 24

Privileged is not antigen specific, while tolerance is