Lecture 20 - Immunity to Cancer

Question 1

What is the elimination phase of cancer surveillance?

Answer 1

immune cells (NK, CD4, CD8, etc) recognize tumor cells and kill them before proliferation

Question 2

What is the equilibrium phase of cancer surveillance?

Answer 2

no true tumor development but mutations arise which decrease immune cell effectiveness

Question 3

What is the escape phase of cancer surveillance?

Answer 3

Rapid proliferation of tumor cells

Question 4

What are the 7 steps to the cancer-immunity cycle

Answer 4

1. cancer cell antigen release
2. antigen presentation
3. APC/T cell priming and activation
4. T cell homing to tumors
5. Infiltration of T cells into tumors
6. recognition of tumor
7. killing of cancer cells

Question 5

What cell kills tumor cells

Answer 5

CD8+ (cytotoxic) T cells

Question 6

What is the action of perforin?

Answer 6

aids in delivering contents of granules into the cytoplasm

Question 7

What is the action of granzymes?

Answer 7

proteases which activate apoptosis

Question 8

What is the action of granulysin?

Answer 8

antimicrobial that promotes apoptosis

Question 9

What are the mechanisms by which tumors avoid immune recognition?

Answer 9

• low immunogenicity
• self antigen
• antigenic modulation
• tumor induced immune suppression
• tumor induced privileged site

Question 10

How does a tumor evade the immune system by:

low immunogenicity

Answer 10

no adhesion, co-stimulatory molecules, MHC molecules present

Question 11

How does a tumor evade the immune system by:

self-antigen treatment

Answer 11

tumor antigens taken up and presented by APCs tolerize T cells

Question 12

How does a tumor evade the immune system by:

antigenic modulation

Answer 12

tumors will not present immunogenic antigens

Question 13

How does a tumor evade the immune system by:

tumor-induced immune suppression

Answer 13

factors secreted by tumor cell inhibit t cells directly (IL-10, TGF-b, PDL-1)

Question 14

How does a tumor evade the immune system by:

tumor induced privileged sites

Answer 14

tumor cells secrete factors that create a cell barrier

Question 15

What two steps of the cancer immunity cycle is PDL 1 involved in

Answer 15

activation of APC/T cells
killing of cancer cells

Question 16

What are the 5 types of cancer immunotherapies

Answer 16

1. cell-based immunotherapy
2. immunomodulators
3. vaccines
4. oncolytic viruses
5. antibody based targeted therapies

Question 17

Explain oncolytic virus immunotherapy

Answer 17

inside a healthy cell, virus does not replicate but it does within a cancer cell. when the cancer cell lyses antigens are presented to T cells by DCs - now T cells are “programmed” to kill cancer cells

Question 18

T/F: CAR-T cell therapy is personalized medicine

Answer 18

TRUE

Question 19

Explain CAR-T cell therapy

Answer 19

T cells are harvested from tumor patient, a retrovirus infects T cells with CD3/CD28, infected cells express anti-CD19, T cells are infused into patient and mediate antitumor activity

Question 20

What do co-inhibitory receptors do

Answer 20

regulate uncontrolled activation of lymphocytes through competing with CD28 molecules

Question 21

What are the two immune checkpoints

Answer 21

CTLA4 and PD1

Question 22

What is ITIM and what is its job

Answer 22

Immunoreceptor Tyrosine-based Inhibitory Motif

recruits phosphatase

Question 23

PDL-1 ____ T cell response

Answer 23

inhibits

Question 24

What do blocking of antibodies on PD-1 or PDL-1 prevent

Answer 24

inhibition of T cells