Adaptive immune response to intracellular pathogens Flashcards
NK cells are part of which immune response ? what is their purpose
Innate
-control pathogen untill an adaptive immune response is triggered
how long after initial infection does it take to launch an adaptive immune response
5-7 days
There are 2 arms to the adaptive immune response, what are they ?
humoral arm - Ab mediated using B cells
cell mediated - CTL mediated using T cells
humoral immunity protects against ____ pathogens whereas Cell mediated protects against _________ ?
extracellular, intracellular
B cells or humoral immunity is MHC class _____ restricted whereas T cells/ cell mediated immunity is MHC class ___ restricted
B cells bind MHC II
T cells bind MHC I
which part of the immune response is more associated w/the production of cytokines
innate immune response
how are NK cells activated once a virus is present ?
downregulation of MHC I expression
**NK cells do NOT need MHC I to be active **
What are the 2 steps required to activate T cells
1 - naive T cells bind respective MCH class on APC 2 - binding of co-stimulatory molecule
in t cell activation, the binding of the co-stimulatory molecule is the result of an interaction b/w what 2 molecules ?
CD28 and B7 molecules
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
L - selectin
T/F Both naive and effector t cells can express L-selectin
F, only naive t cells can express
effector t cells express E and P selectin
If a naive t cell becomes activeated, L-selectin will be downregulated and expressed as ?
E and P-selectin or
LFA and VLA
T/F Only effector t cells express E and P selectin
true
what is the point of effector T cells expressing E and P-selectin as the leave the lymph node looking for site of infection
They are the initial adhesion molecules to the endothelium at the site of infection
what specific cytokines stimulates effector TH1 cells to increase/activate macrophages
IFN-gamma and TNF
what are the 3 specific cytokines the Th2 cells secrete to inhibit macrophages
IL-4, IL-10, IL-13
In general, what are the 2 mechanisms that Th2 CTL are able to lyse the target cell
1 - Granzymes (lytic granules)
2 - Fas-FasL
what are the 3 lytic granules involved in the granzyme pathway for CTL lysis of target cells
perforin - forms pore in membrane
granzymes - serine protease activating apoptosis
granulysin - induces apoptosis
how do granzymes enter the target cell ?
through pores created by perforin
What is caspase activated DNAse (CAD) ?
it is the molecule cause apoptosis/DNA fragmentation in the granzyme pathway
What is endonuclease G (ENDOG) ?
a molecule that causes apoptosis/celaves DNA in the granzyme pathway
There are 3 ways that granzyme B can induce apoptosis, what are they ?
1 - caspase 3 pathway ——–> CAD
2 - directly activate ————> CAD
3 - activate BID —> BAD/BAK —> cytochrome C –> ENDOG
what is the DNAse used in the Fas-FasL mechanism of Th2 CTL ability to lyse target cells
ICAD
Th1 CD4 T cells do 3 things in order to help protect against intracellular pathogens, what are they ?
1 - Increase macrophages via IFN-gamma and TNF
2 - produce cytokines to stimulate CD8 CTL activation
3 - produce cytokines to enhance APC activity
there are 5 evasion mechanisms that intracellular pathogens perform in order to elude host immune responses, what are they ?
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
