Immunology T4

?
  • Created by: Kavita :)
  • Created on: 19-02-15 15:01
Where are CD4+ and CD8+ T cells produced?
Thymus
1 of 26
What are the compartments of the thymus and where are WBCs located in it?
1) Cortex - immature thymocytes + macrophages 2) Medulla - mature thymocytes with dendritic cells, positive and negative selection
2 of 26
What are the stages of thymocyte differentiation?
DN1 > DN2 > DN3 > DN4 - Immature double - thymocytes > Immature double + thymocytes > Mature CD8+4- and CD4+8- thymocytes
3 of 26
Which chain rearranges first in T cell development?
Beta Chain (DN3 B chain protein produced) DN4 rapid cell prolifieration until co-receptor proteins CD8/4 are produced
4 of 26
Why are multiple alpha chain gene rearrangements useful?
To rescue non-productive V-J joins and multiple rounds of rearrangements occur to generate a functional alpha chain
5 of 26
When is the γδ T cells produced?
Early development and has limited antigen specificity and becomes established in specific tissue locations
6 of 26
What does positive selection ensure?
Ensures all T cell bearing cells can interact with self MHC I (CD8+) or MHC II (CD4+)
7 of 26
Where does selection take place?
thymic cortical epithelial cells
8 of 26
Where does -ve selection take place?
Thymic cortex + medulla
9 of 26
What are the 3 features of -ve selection?
1) Driven by APCs 2) T cells with TCRs which react strongly with ubiquitous self antigens are deleted in thymus - prevents autoimmunity. 3) T cells that interact strongly with self MHC molecules are deleted - preventing inappropriate activation
10 of 26
What are the 5 major types of T-cells and their functions?
1) CD8 Tc cells - kill virus infected cells 2) CD4 TH1 - activate infected macrophages - help to B cells 3) CD4 TH17 - enhane neutrophil response, promote barrier integrity 4)TFH cells - B cell isotypes switching, antibody 5) CD4 Treg - suppression
11 of 26
Where do naive T cells encounter antigen?
Recirculation through secondary lymphoid organs
12 of 26
How do T cells enter lymph node cortex?
Enter from blood via high endothelial venules (HEVs) Regulated by adhesion molecules, chemokines. ROLLING (L-selectins) > ACTIVATION (chemokines) > ADHESION (integrins) > DIAPEDESIS (chemokines)
13 of 26
How do T cells exit the lymph node?
Via cortical sinuses
14 of 26
What is the role of L-selectin?
Recognise carbohydrate motifs and is expressed on all T-cells. Addressins on epithelial surface bind L-selectins and bind T-cells weakly to endothelial surface
15 of 26
What is the role of Integrins?
Stabalise binding to APCs, HEVs or endothelia. Bind to adhesion molecules that are important immunoglobulin superfamily
16 of 26
What allows the rolling interaction of T cells when entering lymph node
Binding of L-selectin to GlyCAM-1 and CD34. LFA-1 is activated by chemokines and then binds to ICAM-1 (adhesion molecule). Lymphocyte migrates into lymph node by diapedesis
17 of 26
What are the 5 routes of antigen processing and presentation by dendritic cells?
1) Receptor mediated phagocytosis (MHC II) 2) Macro-pinocytosis (MHC II) 3) Viral Infection (MHC I) 4) Cross-presentation after phagocytic uptake (MHC I) 5) Transfer from incoming dendritic
18 of 26
Name 3 cell adhesion molecules?
ICAM-1 + 2, CD58
19 of 26
Name the 3 signal naive T cells need to become activated?
1) A specific interaction between TCR + MHC + Antigen peptide 2) co-stimulatory interaction which provides a survival & proliferation signal (CD28:B7) 3) A differentiation signal provided by a secreted cytokine
20 of 26
What does the co-stimulatory signal CD28:B7 stimulate?
The production of high affinity IL-2 receptor on activated T cell
21 of 26
Which signal 1, 2 or 3 results in naive CD4+ T cells acquiring different effector functions?
Signal 3
22 of 26
What are the different effector T cells and what do they do?
Treg (TGF-B) - produced when pathogen absent, TFH (IL-6) - found in lymphoid follicals involved in B cell Ab stimulation, TH17 (TGF + IL-6) - early in infection, produce IL-17 recruits neutrophils, TH1 (IL-12, IFN-y) - B cell help, TH2 (IL4) - Bchelp
23 of 26
What does partial signalling result in?
Functional inactivation (anergy) or deleted of T cell. Decreased TCR signalling of GRAIL
24 of 26
How does CD4+ T cell help CD8+ T cell?
Production of CD40L and IL-2 when CD4 interacts with APC. CD40L binds CD40 on APC, APC increases level of B7 and produces 4-IBBL which binds to 4-IBB on CD8+ T cell and B7 binds to CD28 (co-stim), production of IL-2 (growth factor promote CD8+ diff)
25 of 26
Which two proteins from T cells kill the cell?
Granzymes target proteins that regulate apoptosis, Pertorin
26 of 26

Other cards in this set

Card 2

Front

What are the compartments of the thymus and where are WBCs located in it?

Back

1) Cortex - immature thymocytes + macrophages 2) Medulla - mature thymocytes with dendritic cells, positive and negative selection

Card 3

Front

What are the stages of thymocyte differentiation?

Back

Preview of the front of card 3

Card 4

Front

Which chain rearranges first in T cell development?

Back

Preview of the front of card 4

Card 5

Front

Why are multiple alpha chain gene rearrangements useful?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all T-cell development resources »