Lecture 5 - T cell activation (post thymus)

Question 1

following their exit from the thymus, t cells enter the lymphatic system through what?

Answer 1

high endothelial venules

Question 2

what do inactivated T cells leave the circulation via?

Answer 2

cortical sinuses

Question 3

which molecules help T cells to make contact with APCs?

where are these molecules expressed?

Answer 3

cell adhesion molecules

on the surface of T cells

Question 4

which molecule, expressed on T cells, do CAMs interact with to mediate T cell-APC contact?

Answer 4

LFA-1

Question 5

if the TCR recognises the antigen, a signal is sent from which complex?

what does the signal tell the t-cell do?

Answer 5

signal sent from the TCR complex

signal tells the T cell to divide into an effector cell, exit the lymph nodes and move to site of infection to elicit a response

Question 6

how many signals needed for T cell activation?

Answer 6

3

Question 7

which chain of the TCR does signal 1 of activation involve?

Answer 7

CD3 zeta chain

Question 8

what creates signal 1 in T cell activation?

Answer 8

naiive T cells receiving signal from TCR-peptide contact

Question 9

in signal 2 of T cell activation, co-stimulatory molecules bind to what on naiive T cells?

Answer 9

CD28

Question 10

in signal 3 of T cell activation, APCs release cytokines which bind to what on naiive T cells?

Answer 10

upregulated receptors

Question 11

once all 3 signals are given, T cells do what? Which two molecules do they express?

Answer 11

T cells proliferate and express CTLA-4 and ICOS

Question 12

ICOS binds to …… on APC to induce the secretion of …… by T cells?

Answer 12

ICOS ligand / ICOSL

cytokines

Question 13

what does CTLA-4 bind to on APC more avidly than CD28 does?

Answer 13

B7.1 and B7.2

Question 14

what type of signal does CTLA-4 deliver to activated T cells?

Answer 14

negative signal

Question 15

CTLA-4 mutations induce an unwanted autoimmune response. Name 3 diseases in which this is part of the pathology. (hint- 2 are cancers)

Answer 15

type 1 diabetes, melanoma and renal carcinoma

Question 16

CAM molecules mediate which 3 interactions?

Answer 16

T cell and APC interactions

naiive T cell and HEV interactions

T cell and target cell interactions

Question 17

what do the 2 co-stimulatory molecules bind to?

Answer 17

CD28

Question 18

which signal number do co-stimulatory molecules provide in T cell activation?

Answer 18

signal 2

Question 19

what are the 2 co-stimulatory molecules?

Answer 19

B7.1, B7.2

Question 20

B7.1 is associated with which CD molecule?

Answer 20

CD80

Question 21

B7.2 is associated with which CD molecule?

Answer 21

CD86

Question 22

which interleukin is a key cytokine for T cell survival and proliferation?

Answer 22

IL-2

Question 23

when activated, T cells express a high affinity receptor for which cytokine?

Answer 23

IL-2

Question 24

which cytokine, associated with T cell activation, is a target for the immunosuppressive drug cyclosporin?

Answer 24

IL-2

Question 25

what are the 3 cell types which present antigens?

Answer 25

dendritic cells, B cells, and macrophages

Question 26

what is the function of myeloid dendritic cells?

Answer 26

activate naiive T cells

Question 27

which toll like receptors do plasmacytoid dendritic cells express?

Answer 27

7 and 9

Question 28

what type of pathogenic infection are plasmacytoid dendritic cells responsible for dealing with?

Answer 28

viral infection

Question 29

which two types of interferons do plasmacytoid dendritic cells secrete?

Answer 29

kappa and beta

Question 30

which MHC class do macrophages express?

which co-stimulatory molecule do macrophages associate with?

Answer 30

class 2

B7

Question 31

what do macrophages secrete?

Answer 31

inflammatory cytokines

Question 32

signal 2 is given to T cells by co-stimulatory molecules bind to CD28 on T cells.

how can signal 2 be given in an alternative way to T cells?

Answer 32

antigen binding to B cell receptors which upregulates B7 (a co-stimulatory molecule which delivers signal 2 to T cells)

Question 33

cross presentation involves the uptake of what by dendritic cells?

Answer 33

exogenous antigens

Question 34

in cross presentation, exogenous antigens are presented on which molecule?

Answer 34

MHC class 1

Question 35

what does cross presentation of antigens allow dendritic cells to do?

Answer 35

activate naiive CD8+ T cells - they can then kill other cells

Question 36

what do CD8+ T cells do in simple terms?

Answer 36

kill other cells

Question 37

what do CD4+ T cells do in simple terms?

Answer 37

secrete cytokines

Question 38

what are the 3 subgroups of T cell (3 stages in a T cell’s life)?

hint- starts with naiive T cells

Answer 38

naiive
effector
memory