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Flashcards in Ch 12 Deck (32):
1

what happens when the immune system goes awry?

selection in thymus and bone marrow remove overtly self-reactive T and B cells during development
adaptive encounters self that wasn't present during selection
autoimmunity

2

has several mechanisms to deal with potentially self-reactive cells

adaptive

3

selective unresponsiveness

tolerance

4

recognition self-MHC I or II

positive selection

5

not overtly self-reactive to self peptides

negative selection

6

increases efficiency

AIRE gene

7

what cells slip through selection

potential autoreactive T cells

8

tolerance: requires that when adaptive does recognize self, it adopts nondestructive strategy

anergy
CTLA-4
regulatory T cells

9

state of lymphocyte nonresponsiveness
occurs following pMHC engagement or free epitope engagement
absence of instruction from APC or from CD4+, immune system does not respond
form of regulation imposed upon activation of naïve T and B cells
cells are not killed but remain in circulation, unactivated

anergy

10

moces to outer cell membrane and binds with CD80/86 with 100-fold greater avidity than CD28

CTLA-4

11

What does CTLA-4 inhibit

IL-2 mRNA expression by T cell and progression into cell cycle

12

T cells constitutively express

CD28

13

when t cells are engaged with CD80/86, it does what

stimulates IL-2 and IL-2R production and enter into cell cycle

14

helps maintain tolerance
inhibit activity of autoreactive lymphocytes

regulatory t cells

15

what are the two classes of regulatory t cells

t regulatory
t suppressor

16

express both CD4 and CD25
thought to be important inhibitors of immune-mediated inflammatory diseases

t regulatory

17

CD8+
inhibit activation and proliferation of CD4+ t cells inducing Th1 cells

t suppressor

18

express both CD4 and CD25
implicated in prevention of some autoimmune responses and some responses against nonself
present in absence of intentional immunization
activation requires TCR
inhibitory effects are nonspecific
undergo + and - selection
express Foxp3 nuclear transcription factor

CD4+ t regulatory cells

19

inhibitory subpopulations of CD8+ t cells
do not express CD28
presence associated with suppression of graft rejection and inhibition of some autoimmune diseases
activation requires CD4+ T helper cells
express Foxp3 nuclear transcription factor

CD8+ suppressor cells

20

subset of CD4 T cells
do not diminish inflammatory responses
promote inflammatory events
stimulated by IL-23
Secrete IL-17
induces production of inflammatory cytokines

Th17 cells

21

attracts to inflammatory sites

IL-17

22

cytokines

IL-1
IL-6
TGF-beta
G-CSF
IL-8

23

chemokine

IL-8

24

mutually inhibit one another's activity through cytokine signals

Th1/Th2 paradigm

25

proliferation and growth

IL-2

26

proliferation and growth, isotype switch to IgG1, IgG3, IgG4, IgE
inhibit maturation along Th1 pathway

IL-4

27

isotype switch to IgG1, IgG3
promotes maturation along Th2 pathway and inhibits Th1 pathway

IL-10

28

stimulates production of IFN-gamma that in turn drives development of Th0 to Th1
promotes maturation along Th1 pathway and inhibits Th2 pathway maturation

IL-12

29

acts as chemoattractant and induces production of proinflammatory by cytokines

IL-17

30

induces differentiation of Th17 cells and production of IL-17

IL-23

31

isotype switch to IgA
inhibits activity

TGF-beta

32

differentiation into Th1 pathway
isotype switch to IgG1, IgG3
inhibition of Th2 cells

IFN-gamma