Unit 3 Lecture 18 and 19

Question 1

What are the only conditions that let T cells live?

Answer 1

• Positive selection to self-MHC proteins

- Negative selection to self-peptides

Question 2

When a T cell can live, what happens?

Answer 2

It becomes immunocompetent and leaves the thymus

Question 3

Define adaptive immunity

Answer 3

Body’s ability to recognize and defeat specific invading agents (bacteria, viruses, and foreign stuff)

Question 4

What are the two ways to distinguish adaptive immunity from innate immunity?

Answer 4

1. specificity for foreign antigens and tolerance for self proteins
2. memory of past foreign antigens

Question 5

What are the two types of adaptive immunity?

Answer 5

1. Cell mediated immunity

2. Antibody mediated immunity

Question 6

Cell mediated immunity involves what type of T cell

Answer 6

Cytotoxic T cells

Question 7

Antibody mediated immunity involves what type of T cell?

Answer 7

Helper T cells

Question 8

What must be on both T cells in order for cell and antibody mediated immunity to work?

Answer 8

T cell receptors

Question 9

What can also be found on the surface of T cells during antibody mediated immunity?

Answer 9

proteins used by B cells

Question 10

What protein do foreign antigens connect to during cell mediated immunity?

Answer 10

MHC I protein

Question 11

What protein do foreign antigens connect to during antibody mediated immunity?

Answer 11

MHC II protein

Question 12

How is cell mediated immunity specific?

Answer 12

defends the body against SPECIFIC pathogens that live INSIDE our cells

Question 13

How is antibody mediated immunity specific?

Answer 13

defends the body against SPECIFIC pathogens that live OUTSIDE of cells

Question 14

How are cell mediated immunity and antibody mediated immunity tolerant?

Answer 14

they both do NOT recognize self-antigens presented by MHC I and II but they are TOLERANT of self-proteins

Question 15

What are the 2 main properties of antigens?

Answer 15

1. Immunogenicity

2. Reactivity

Question 16

Define immunogenicity

Answer 16

antigens stimulate proliferation of specific lymphocytes and antibodies

Question 17

Define reactivity

Answer 17

antigens react with activated lymphocytes and antibodies developed/ released in response to them

Question 18

What is a complete antigen?

Answer 18

An antigen that exhibits both immunogenicity and reactivity AND includes foreign proteins, nucleic acids, lipids and large polysaccharides

Question 19

What are epitopes?

Answer 19

immune responses generated against parts of the antigens

Question 20

AGAIN, what conditions allow for T cells to live?

Answer 20

• positive selection to self-proteins

- negative selection to self-peptides

Question 21

Where do T cells go after they become immunocompetent and leave the thymus?

Answer 21

Go to lymphatic tissue

Question 22

What conditions activate T cells to proliferate and differentiate

Answer 22

Antigen recognition with costimulation

Question 23

What causes T cells to become inactivated or die after leaving the thymus?

Answer 23

antigen recognition without costimulation or deletion signal

Question 24

What is the different between cell mediated and antibody mediated immunity?

Answer 24

cell mediated -intracellular pathogens

antibody mediated - extracellular pathogens

Question 25

What are the steps for cell-mediated immune responses to occur?

Answer 25

1. Antigen presentation 2. Antigen recognition 3. Activation 4. Proliferation and differentiation 5. Action (destruction of infected cell)

Question 26

What allows cells to begin antigen presentation?

Answer 26

Antigen presenting cells (APCs)

Question 27

What are the major APCs?

Answer 27

- Dendritic Cells (DCs) - Macrophages - Activated B cells

Question 28

What is the major initiator of adaptive immunity?

Answer 28

Dendritic cells

Question 29

What do dendritic cells do?

Answer 29

Travel to lymph nodes and secondary lymphatic organs where they present antigens to T cells

Question 30

What additional things aids in antigen recognition during cell mediated immunity?

Answer 30

Cluster designation markers * the red dangly thing coming off of helper T cells and cytotoxic t cells

Question 31

What happens during antigen presentation via MHC II proteins

Answer 31

APCs present EXOGENOUS (outside) antigens w MHC II molecules

Question 32

What happens during antigen presentation via MHC I proteins

Answer 32

Infected body cells present ENDOGENOUS (inside) antigens w MHC I molecules

Question 33

What additional thing aids in antigen recognition during cell mediated immunity?

Answer 33

Cluster designation markers * red dangly thing on help and cytotoxic T celsl

Question 34

What are the 2 types of cluster designation markers?

Answer 34

CD4 and CD8

Question 35

What cluster designation marker do helper T cells show?

Answer 35

CD4

Question 36

What do CD4 cluster designation markers only bind to?

Answer 36

MHC II molecules (on all APCs)

Question 37

What cluster designation marker do cytotoxic T cells show?

Answer 37

CD8

Question 38

What do CD8 cluster designation markers only bind to?

Answer 38

MHC I molecules (on all nucleated cells)

Question 39

During activation, what causes T cells to complete activation or abort activation?

Answer 39

Costimulators

Question 40

What do T cells do without costimulation?

Answer 40

- become tolerant to antigen - unable to divide - do not secrete cytokines

Question 41

What do T cells do with costimulation?

Answer 41

- enlarge, proliferate, and forms clones | - differentiate and perform functions whether helper or cytotoxic

Question 42

What do cytokines do?

Answer 42

Costimulate T cells and T cell proliferation

Question 43

What is the main type of cytokine?

Answer 43

Interleukin (IL-1)

Question 44

What releases interleukins?

Answer 44

macrophages

Question 45

What do interleukins (IL-1) costimulate T cells to do?

Answer 45

1. Release interleukin 2 (IL-2) | 2. Synthesize more IL-2 receptors

Question 46

What is interleukin 2

Answer 46

- Key growth factor - makes positive feedback cycle telling T cells to divide - fights cancer

Question 47

What are other types of cytokines?

Answer 47

- Perforin and lymphotoxin = cell toxins - gamma interferon - inflammatory factors

Question 48

What do gammer interferons do?

Answer 48

enhances the killing power of macrophages

Question 49

What do Helper T cells do when the recognize the presented antigen?

Answer 49

- stimulate proliferation of other T cells (important for cell & antibody mediated immunity) - stimulate B cell to proliferate and differentiate (important for antibody mediated immunity)