T Cell Development and Effector Function Flashcards Preview

MSS-IHL Final Exam > T Cell Development and Effector Function > Flashcards

Flashcards in T Cell Development and Effector Function Deck (65):
1

T Cell Receptor

V (D) J recombination
uses RAG proteins
V region has 3 hypervariable regions
TCR remains membrane bound
non class switching or affinity maturation**
majority alpha beta

2

smaller subset of T Cell Receptors?

gamma-delta
**only 5-10%

3

why is it important to have no affinity maturation in T Cell receptor?

increases the likelihood they will recognize a self peptide

this could lead to autoimmunity

4

what does the TCR recognize?

1-3 residues on the MHC-peptide complex

much weaker interaction than with antibodies

5

what is necessary for TCR binding?

binding to both the antigen and the MHC molecule

6

beta chain locus for TCR?

on chromosome 7
includes D regions

**undergo combinatorial and junctional diversity

RAG1 and RAG 2 proteins mediate recombination

7

double negative cell

naive mature T cell that does not express the CD4 or the CD8

8

double positive cell

express both CD4 and CD8 on the cell

9

what will express CD4?

something that interacted with MHC II

10

wha will express CD8?

something that interacted with MHC I

11

what T cells make it to the periphery

those that had weak affinity for MHC and self antigens

12

positive selection

weak interacting TCRs with antigen/MHC are selected to survive

13

negative selection

strong interacting TCRs with antigen/MHC are selected against and undergo apoptosis

14

where does positive and negative selection occur

cortex

15

as maturing T cell moves to the medulla what happens?

becomes single positive

16

MHC restriction

TCR only recognizes an antigen bound to MHC

17

what happens if you can't express MHC class I

will only have CD4 (no CD8 expression)

18

cell-mediated immunity involves what to processes?

combats intracellular microbes (ingested microbes and viruses

T cells recognize peptides presented in the context of MHC (APC's and infected host cells)

19

APCs express what MHC?

MHC class II (also Class I)

20

what cells express MHC class I?

all nucleated cells

21

what happens when naive CD4 cells are activated?

change their IL-2 receptor to higher affinity
can undergo clonal expansion and mature to effector or memory CD4 T cells

22

what do you need to make sure if you remove a patient's spleen?

that they are up to date on their immunizations

23

what makes up the TCR complex?

CD3, zeta chain, and TCR
on all the T cells

24

CD28

interacts with B7 molecules on APC
this increases IL-2 production
activate the T cell
after T cells have been activated, the CTLA-4 is increased - inhibitory structure

25

CTLA-4

outcompetes the CD28 and decreases IL-2 production

26

cross-presentation

dendritic cell can place antigens on MHC class I and II

CD4 secretes cytokines that help to activate the CD8 cells

27

activation of CD8 T cells

can be activated directly but also by cross-presentation CD-4 cytokines

28

CD40L

helps to prolong the interaction of the T cell with the APC

29

what happens to IL-2 receptor during activation?

increases its affinity for IL-2

30

IL-2

survival, differentiation of the CD4 and CD8 T cells

31

TGF-beta

inhibition of T cell activation

32

IL-4

switches B cell to IgE
**Th2

33

IL-5

activation of eosinophils
**Th2

34

Interferon-gamma

activation of macrophages

35

what would happen after you block CTLA-4 action?

would not be able to inhibit the T cell proliferation and they would always stay on

**may be beneficial in anti-cancer therapy

side-effects: autoimmunity

36

types of CD4 T cells?

Th2, Th1, Th17, T regulatory cells

37

Th1 cells

produce IFN-gamma
activate macrophages

38

Th2 cells

produce IL-4, IL-5, and IL-13
promote humoral immunity

39

Th17 cells

produce IL-17
involved in host defense AND pathogenesis of autoimmune disease

40

T regulatory cells

suppress the T cell function

41

CD40L

on the CD4 T cells that interacts with CD40 on macrophage

leads to macrophage activation

42

what happens with asthma (which T cells)?

Th2 which activates eosinophils and mast cells

43

what activates Th1 formation?

IL-12 and IFN-gamma

44

what activation Th17 formation?

IL-6**
TGF-beta
IL-1
IL-23
GM-CSF

45

what activates Th2 formation?

TSLP

46

what do Th1 cells do?

secrete IFN-gamma

also produce TNF-alpha

47

what does IFN-gamme release from Th1 cells cause?

activation of macrophages
stimulation of complement binding
Class II MHC and B7 expression

48

what may lead to multiple sclerosis?

Th1 response

49

what does the classical macrophage activation lead to?

enhance microbial killing

50

what do Th2 cells release?

IL-4, IL-5, and IL-13

51

IL-4

-activate B cells to produce IgE
-also activate the macrophage to increase fibrosis/tissue repair (alternative)

52

IL-5

activate eosinophils

53

alternative macrophage activation?

leads to fibrosis and tissue repair
**stimulated by IL-4 and IL-13

54

Th17

secretes IL-17

55

IL-17

recruits the leukocytes to sites of infection
functions to maintain epithelial barrier and important in gut tolerance

56

phagocyte with ingested microbes causes what?

MHC class II presented antigens
activates Th1 and Th17 CD4 T cells

57

infected cell with cytoplasm microbes causes what?

MHC class presented antigens
activates the CD8 T cells

58

what adhesion molecules move T cells to the lymph node?

expression of L selectin and LFA-1 and CCR7 on naive T cells

59

what adhesion molecules move T cells to sites of infection?

E and P selectin, LFA-1 and VLA-4 and CXCR3 (chemokines)

** T cells get to where they need by homing signals

60

what activates a naive CD4 cell to become Th1?

IL-12
dependent on antigen-recognition

basis for delayed-type hypersensitivity reaction

61

macrophage activation by Th1 cells?

increases ROS and NO, secretes cytokines TNF, IL-1, IL-12, increased MHC and B7

62

PPD test?

example of a Delayed-type hypersensitivity reaction of the Th1 activation

63

balance between the Th1 and Th2 cells?

Th2 cell cytokines shuts down the classical activation of macrophages (microbicidal)

defects in either can cause problems
ex/ leprosy

64

what happens with CD8 T cell activation?

secretion of granzymes and perforins

perforins poke holes and granzymes enter and activate the caspases > apoptosis

65

cooperation between the CD4 and CD8?

yeah.