Adaptive immune response to intracellular pathogens

Question 1

NK cells are part of which immune response ? what is their purpose

Answer 1

Innate

-control pathogen untill an adaptive immune response is triggered

Question 2

how long after initial infection does it take to launch an adaptive immune response

Answer 2

5-7 days

Question 3

There are 2 arms to the adaptive immune response, what are they ?

Answer 3

humoral arm - Ab mediated using B cells

cell mediated - CTL mediated using T cells

Question 4

humoral immunity protects against ____ pathogens whereas Cell mediated protects against _________ ?

Answer 4

extracellular, intracellular

Question 5

B cells or humoral immunity is MHC class _____ restricted whereas T cells/ cell mediated immunity is MHC class ___ restricted

Answer 5

B cells bind MHC II

T cells bind MHC I

Question 6

which part of the immune response is more associated w/the production of cytokines

Answer 6

innate immune response

Question 7

how are NK cells activated once a virus is present ?

Answer 7

downregulation of MHC I expression

**NK cells do NOT need MHC I to be active **

Question 8

What are the 2 steps required to activate T cells

Answer 8

1 - naive T cells bind respective MCH class on APC
2 - binding of co-stimulatory molecule

Question 9

in t cell activation, the binding of the co-stimulatory molecule is the result of an interaction b/w what 2 molecules ?

Answer 9

CD28 and B7 molecules

Question 10

in order for T cells to get from the Lymph node to the site of infection, what receptor on naive T cells must be downregulated

Answer 10

L - selectin

Question 11

T/F Both naive and effector t cells can express L-selectin

Answer 11

F, only naive t cells can express

effector t cells express E and P selectin

Question 12

If a naive t cell becomes activeated, L-selectin will be downregulated and expressed as ?

Answer 12

E and P-selectin or

LFA and VLA

Question 13

T/F Only effector t cells express E and P selectin

Answer 13

true

Question 14

what is the point of effector T cells expressing E and P-selectin as the leave the lymph node looking for site of infection

Answer 14

They are the initial adhesion molecules to the endothelium at the site of infection

Question 15

what specific cytokines stimulates effector TH1 cells to increase/activate macrophages

Answer 15

IFN-gamma and TNF

Question 16

what are the 3 specific cytokines the Th2 cells secrete to inhibit macrophages

Answer 16

IL-4, IL-10, IL-13

Question 17

In general, what are the 2 mechanisms that Th2 CTL are able to lyse the target cell

Answer 17

1 - Granzymes (lytic granules)

2 - Fas-FasL

Question 18

what are the 3 lytic granules involved in the granzyme pathway for CTL lysis of target cells

Answer 18

perforin - forms pore in membrane
granzymes - serine protease activating apoptosis
granulysin - induces apoptosis

Question 19

how do granzymes enter the target cell ?

Answer 19

through pores created by perforin

Question 20

What is caspase activated DNAse (CAD) ?

Answer 20

it is the molecule cause apoptosis/DNA fragmentation in the granzyme pathway

Question 21

What is endonuclease G (ENDOG) ?

Answer 21

a molecule that causes apoptosis/celaves DNA in the granzyme pathway

Question 22

There are 3 ways that granzyme B can induce apoptosis, what are they ?

Answer 22

1 - caspase 3 pathway ——–> CAD
2 - directly activate ————> CAD
3 - activate BID —> BAD/BAK —> cytochrome C –> ENDOG

Question 23

what is the DNAse used in the Fas-FasL mechanism of Th2 CTL ability to lyse target cells

Answer 23

ICAD

Question 24

Th1 CD4 T cells do 3 things in order to help protect against intracellular pathogens, what are they ?

Answer 24

1 - Increase macrophages via IFN-gamma and TNF
2 - produce cytokines to stimulate CD8 CTL activation
3 - produce cytokines to enhance APC activity

Question 25

there are 5 evasion mechanisms that intracellular pathogens perform in order to elude host immune responses, what are they ?

Answer 25

1 - Inhibit proteosome activity
2 - Block transport proteins (TAP)
3 - Remove MHC I (No CTL's)
4 - Block MHC I synthesis (No CTL's)
5 - produce decoys