L16: Activation And Expansion Of T Cells Flashcards
Where are naive T cells made
In the thymus
How is a naive T cell activated
Antigen is presented by the dendritic cell to the naive T cell
How do dendritic cells present the antigen to the naive T cell
In MHC complex
Where are naive T cells activated by the dendritic cells
In the lymph nodes
Which receptors on the dendritic cell allow it to migrate to the site of infection
Chemokine receptor 1,2,5,6
To stop the dendritic cell from migrating to the site of infection and make it migrate it to the Lymph node what happens to the chemokine receptors
Chemokine receptors are down regulated
Which receptor switches on to allow the migration of the dendritic cell to the lymph node
CCR7
When the dendritic cell reaches the lymph node what changes occur to the dendritic cell
1) express MHC molecule with the antigen
2) express co stimulatory molecule called B7
What are the 3 signals that occur when dendritic cells bind to naive T cells so they are activated
Signal 1 : activation
Signal 2: survival
Signal 3: differentiation
How does the first signal (activation occur)
MHC class 2 on dendritic cell binds to T cell receptor on naive T cell
What happens in the second signal (survival)
B7.1 and B7.2 on dendritic cells binds to CD28 on T cells
What is B7.1 and B7.2 also known as
CD80 = B7.1 CD86= B7.2
What happens in signal 3 (differentiation)
Dendritic cells release cytokines of IL-6, IL-12, TGF-BETA, IL-4 which bins to T cells
What do naive T cells differentiate into
Effector T cells
What do effector T cells later become if they are retained
Memory T cells
Name the types of effector cells
CD8 cytotoxic cells CD4 th1 cell CD4 th2 cells CD4th17 TFH CD4 reg T cells
Which is the only effector T cell that binds to MHC class 1
CD8 cytotoxic T cell
What type of protein does MHC class 1 present
Endogenous protein
Name a pathogen that infects the cell intracellularly and therefore is presented on the MHC class 1
Viruses
What pathogen do CD8 T cells target
Viruses
Some intracellular bacteria
What is the main function of CD4th1 cells
Activate infected macrophages
Help B cells for antibody production
Which pathogens do CD4th1 cells target
Microbes are present in macrophages
What is the main function of CD4 th2 cells
Help B cell antibody production especially switching to iGE
What pathogen do CD4 TH2 cells target
Helminth parasites
What is the main function of the TH17 cells
Enhance neutrophil responce
What does CD4 th17 target
Klebsiella pneumonia
Fungi
What is the main function of TFH cells
B cell isotope switching
Antibody production
What pathogen does TFH cells target
All types
How do CD8 T cells kill an infected cell
1) granules in T cell contain perforin and granzymes
2) perforin plugs a hole into the membrane of the infected cell
3) granzymes enter the infected cell to activate opotosis
Or
1) fas ligand binds to fas on target cell that triggers apoptosis
Because we have different subtypes of CD4 T cells how do we differentiate different CD4 T cells
With the production of different cytokines
Which cytokine allow the differentiation of CD4 th1 cells
IL-12
What cytokine do CD4 th1 cells secrete when they are stimulated by an antigen
IFN-gamma
What does IFN-gamma do to the differentiation of TH1 cells
Enhance it
Which cytokine drives the differentiation of TH2 cells
IL-4
What cytokines do th2 cells secrete
IL-4
IL6
IL-13
What is the role of IL-4
Promote B cell switching to ige
Which cytokine stimulates the differentiation of CD4 TH17 cells
IL-1beta
IL-6
IL-21
TGF-beta
What cytokines do TH17 cells secrete
IL-17
What cytokine does TH17 not secrete
IFN-gamma
Which cytokine increases the differentiation of TFH
IL-21
