cytotoxic T cells Flashcards Preview

Basic Immunology- Module 1 > cytotoxic T cells > Flashcards

Flashcards in cytotoxic T cells Deck (84)
Loading flashcards...
1

How is endogenous antigen broken up beofre entry to the ER?

proteasome

2

Describe the peptide binding groove on MHC?

slightly curved beta sheets as a base with two alpha helices on top

3

How many amino acids can the MHC I bind?

8-10

4

How many amino acids can the MHC-II bind?

13-25

5

How are TCRs formed?

by rearranging non-continous gene segments

6

What is the most important costimulation give to naive T cells?

CD28- CD80/86

7

What happens to a naive T cell if there is peptide recognition in the absence of costimulation?

activation induced cell death or anergy

8

What is the function of CTLA4?

binds CD80/86 but is inhibitory

9

What is the difference between the antigens picked up in the spleen and lymph nodes?

spleen will pick up bloodstream antigens whereas lymph nodes will pick up antigen in tissues

10

How can dendritic cells be activated?

TLRs and other PRRs; tissues damage or cytokines produced during the inflammatory response

11

Where are dendritic cells foudn in the lymph nodes?

cortex of the lymph node in the T cell areas

12

Where are macrophages foudn in the lymph ndoes?

throught the lymph node but concentrated mainly in the marginal sinus and medullary cords

13

What happens in the marginal sinus of hte lymph node?

afferent lymph collects before percolating through the lymphoid tissue

14

What happens in the medullary cords of the lymph nodes?

effect lymph collects before passing via the effect lymphatics into the blood

15

What is the function of plasmacytoid DCs?

sentinels for viral infections and produce large amoutns of type I IFNS

16

What receptors do dendritic cells have for phagocytosing antigen?

complement; Fc; C-type lectins

17

What is the nonsepcific method that dendritic cells have for the uptake of antigen?

macropinocytosis

18

What is the benefit of dendritic cells using macropinocytosis in addition to phagocytic receptors to ingest antigen?

microbes that have evolved strategies to escape recognition by phagocytic receptors e.g bacteria with thick capsules are ingested

19

What is cross presentation?

when viral antigens which enter dendritic cells via endocytic or phagocytic vesicles may be diverted to the cytosol for proteasomal degrataion and loaded onto MHC I molecules

20

what is hte purpose of cross presentation?

viruses that do not directly infect DCs can stimulate the activation of CD8 cells

21

In what infections are dendritic cells from the site of infection able to transfer antigen to resident dendiritc cells in the lymph nodes ?

herpes simplex or influenza

22

What chemokine receptor is upregulated in licensed dendritic cells?

CCR7

23

What is the function of CCR7 being upregulated by activated DCs?

responds to CCL21 which is produced by lymphoid tissue and facilitiates their migration into local lymphoid tissue; also contributes to their enhanced APC function

24

As well as MHC and costimualtory molecules CD80 and CD86, what else do activated DCs express?

adhesion molecules e.g DC-SIGN; secrete CCL19

25

What is the function of CCL19 secreted by DCs?

specifically attracts naive T cells

26

What cytokine do activated T cells secrete?

IL2

27

What are the functions of IL-2 produced by activated T cells?

maintenance of Tregs; augment T cell proliferation and survival; affects the balance of effector and memory T cells that develop in a primary response to antigen

28

Which cells produce IFNy?

Th1; NK cells; CD8

29

By what process do cytotoxic T cells kill tagret cells?

extrinsic or intrisinc apoptotic pathways

30

How is transciption of IL-2 in activated T cells caused?

antigen recognition by the T cell receptors induces the activation of NFAT; AP-1 and NfkB which bind to the promotor region of IL2 gene