Effector Mechanisms of T Cell-Mediated Immunity

Question 1

ways t cells can become activated

Answer 1

phagocytes with ingested microbes or infected cells, both present Ag to naive t cells via MHC I/II

Question 2

Discovery of Cell-Mediated Immunity

Answer 2

immunity transferred from one lab animal to a naïve animal only by cells (T-cells)

T cells transferred, but macrophages become activated to kill

Question 3

Subsets of CD4+ helper T lymphocytes distinguished by?

Answer 3

cytokines produced

Question 4

subsets of Th

Answer 4

Th1
Th2
Th17

Question 5

Th1

Answer 5

Question 6

Th2

Answer 6

Question 7

Th17

Answer 7

Question 8

general properties of t cell cytokines
always produced?
act over what distances?
only one action per cytokine?
redundancy?

Answer 8

transiently produced in response to Ag
acts in autocrine/paracrine way
each cytokine has multiple possible actions
redundant: some may share same actions

Question 9

transient cytokine production significance

Answer 9

only made when needed for a response

Question 10

auto/para significance if cytokines

if not accomplsihed?

Answer 10

localizes the effect, if not=autoimmuine or severe infection

Question 11

multi effect of cytokines function

Answer 11

provides diverse actions but can limit clinical utility of cytokines (redundancy)

Question 12

redundancy of cytokine significance

Answer 12

blocking one cytokine may not produce desired effect

Question 13

action and source of: 
IL-2
IFN-gamma 
IL-4 
IL-5 
IL-17
IL-22
TGF-B

Answer 13

Question 14

Th1 cells basic

Answer 14

induced with microbes in APC, presentation via MHC II to CD4 cells
Th1 produced: IFN-gamma released to cause classical macrophage activation

Question 15

Activation of macrophages by Th1 lymphocytes

Answer 15

classical activation
MHCII binds TCR of CD4 cell/Th1, induced signal for CD40L to CD40 on APC which causes costim for IFN-gamma from Th1 to macrophage receptor to activate killing functions, increased MHC and costimulator production and secretion of cytokines

Question 16

macrophage responses in classical immunity and their role in cell-mediated immunity
killing?
cytokines?
t cells?

Answer 16

w

Question 17

Th1 cell development

Answer 17

IL-12 from APC and IFN-gamma from NK cells drive cell expression to become Th1
REQUIRES AN AG ACTIVATED CD4 CELL

Question 18

Th2 cells basic
induced by?
signature cytokines?

Answer 18

Induced by parasitic worm infections

Signature cytokines: IL-4, IL-5, IL-13

Question 19

Th2 cell activation and effector pathways

Answer 19

note the Tfh cell working on b cell: IgE produced, works w mast cells and eosinophils at the Fc receptors

Question 20

IgE- and eosinophil-mediated killing of helminths

Answer 20

IgE binds Fc receptors on the eosinophils which allow cell to recognize Ag of the worm and target it
IL-5 activates the eosinphil to degranulate causing the killing of the worm

Question 21

Classical and alternative macrophage activation compared/relation

Answer 21

Th1 cytokine IFNgamma inhibits Th2 and Th17 developmental possibilities
Th2 cytokines IL-4 & IL13 inhibit classicalmacrophage activation (M1)

Question 22

events of hypersensitivity/allergies

Answer 22

Immediate hypersensitivity reactions are initiated by the introduction of an allergen, which stimulates TH2 reactions and immunoglobulin E (IgE)
production.
IgE binds to Fc receptors (FcΕRI) on mast cells, and subsequent exposure to the allergen activates the mast cells to secrete the mediators that are responsible for the pathologic reactions of immediate hypersensitivity.

Question 23

. Balance between Th1 and Th2 cell activation determines?

Answer 23

outcome of intracellular infections, want more Th1 to activate killing function

Question 24

Th2 cell

development

Answer 24

REQUIRES AG ACTIVATED T CELL EXPOSED TO IL-4 TO INITIATE TFS FOR GENE EXPRESISON TO TH2

Question 25

Th17 major cytokines and functions

Answer 25

IL-17, IL-22

Recruitment of neutrophils and resulting in inflammation to combat bacterial/fungal infections

Question 26

Th17 response pathway

Answer 26

Question 27

Th17 cell

development

Answer 27

STILL REQUIRES AG-ACTIVATED T CELL, USES IL-1, IL-6, IL-23, AND TGF-B TO INDUCE THE TFS

Question 28

function of CD8+ cytotoxic T lymphocytes with infected cell
TCR complex?
enzymes?

Answer 28

m

Question 29

. Cooperation between CD4+ and CD8+ T cells in eradication of
intracellular infections

Answer 29

Question 30

mycobacteria counter to immunity

Answer 30

prevent phagolysosome formation

Question 31

HSV counter

Answer 31

inhibits TAP/Ag presentation

Question 32

CMV counter

Answer 32

prevents Ag presentation with removal MHC molecules from the ER

Question 33

EBV counter

Answer 33

inhibition Ag presentation with proteasomal inhibition
AND
IL-10 production causes the inhibition of macrophage and dendritic cell activation

Question 34

pox virus counter

Answer 34

production soluble cytokine receptor to prevent effector cell activation

Question 35

Host counter defense to reduced MHC class I display on cell surfaces:

Answer 35

activation of natural killer cells

Question 36

HIV effect

Answer 36

infects/kills CD4 cells