Immunology Lecture 11. Flashcards Preview

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Flashcards in Immunology Lecture 11. Deck (25):
1

What is tolerance?

lack of response to a specific antigen

2

What can tolerance involve?

elimination, neutralization, generation of unique cell populations

3

Why is tolerance important?

potential for auto reactivity with induce rearrangements in V regions of T and B cells - failure for tolerance makes autoimmune diseases

4

What type of cell expresses AIRE?

medullary epithelial cell in the thymus

5

What are the two major mechanisms of tolerance induction?

deletion or reactive cells or ANERGY

6

What does lack of second signal cause? What is the second signal in T cells?

ANERGY CD28/B7

7

What are T regulatory cell markers?

FOXP3+, CD25+, CD4

8

TGF-B

induces T regulatory cells

9

IL-10

produce immune dampening

10

IPEX

the result of no FOXP3 = enteropathy, diabetes, thyroiditis, dermatitis

11

Why are tumor cells not killed by the immune system?

cancer cells produce TGF-B which induce T regulatory cells, T regulatory cells release IL-10, no stimulation of cytotoxic T cells happens, so T cell is not killed

12

How are B cells activated by T cells?

CD40/CD40L and cytokines

13

Why is T helper response for B cells important?

no AIRE expressed in bone marrow - more likely to respond to self

14

What does no germinal centers in lymph nodes suggest?

no t cell help for b cells

15

How does dose induce/maintain tolerance?

a higher or lower does outside the range of immunological response induces tolerance

16

How does maturity induce tolerance?

more easily generated in immature animals

17

How does immunogenicity induce tolerance?

weak immunogen requires less stringent regime for induction than a strong one

18

How does the form of a substance induce tolerance?

aggregated can be immunogenic, but disaggregated can become tolerogenic (related to antigen processing/presentation)

19

CTLA-4

binds to B7 much more tightly than CD28 and blocks further activation of T lymphocyte

20

How does portal of entry induce tolerance?

subcutaneous/intradermal usually IMMUNOGENIC - IV/orally usually induce tolerance

21

What type of antigen induces humoral immunity and CMI?

protein antigens - not polysaccharides and lipids for CMI

22

What is FOXP3?

transcription facot - turns down immune response in t reg cells

23

What is antigen blocking?

antibody sequestering antigen - binds antigen and prevents it from being recognized by other antigen recognizing cells

24

IgM immune complex does what?

binds to antigen presenting cells and aids in presentation to b and t cells - ENHANCES immune response

25

IgG immune complex tends to do what?

SUPPRESS immune response - like cross linking