Cell Meditated Immunity - Bowden (Completed) Flashcards
What organs are T cells activated in? 7
Lymph organs
What is the only cell capable of activating a naive T cell? 7
Dendritic cells
What cells are activated by macrophages and B cells? 7
Memory T cells
What is responsible for activating B cells and macrophages? 7
CD4 T helper cells
How do T cells enter lymph nodes? 8
Across High Endothelial Venules (HEV)
What happens if a naive T cell doesn’t encounter Ag while in a lymph node? 8
They leave and enter the next lymph node via a HEV looking for Ag
What causes proliferation and differentiation of T cells? 8
IL-2
CD4 increase (100 - 1000x)
CD8 increase (100,000x)
What is the maximum amount of time it will take for an Ag to be bound by naive T cells while in a lymph node? 8
Within two days
How long does it take for adaptive cells to leave the lymph node once activated? 9
Five days
During an interaction what does CD4 and CD8 bind to? 10
They both bind to the appropriate HLA Class (I or II)
Besides Ag binding via a HLA Class II, what else provides a stimulating signal between a B cell and a CD4 T cell? 10
(T cell) CD28—-B7-1/B7-2 (B cell)
B7-1/B7-2 also called CD80
What’s another name for B7-1/B7-2 activation receptor? 10
CD80
What are the adhesions molecules between APC and T cell? 12
(T cell) CD2 — LFA3 (APC)
T cell) LFA-1 — ICAM-1 (APC
How do integrins move from weak affinity to high affinity to stabilize interactions between T cells and APC? 13
Chemokines receptors change the affinity
What happens if a DC binds a naive T cell with only the HLA Class II + bacterial peptide? 14
If there is no CD80 (B7-1/2) to CD28 interaction the T cell will either not respond or become anergic
What is the first gene product produced minutes after T cell activation? 16
transcription factor C-Fos
C-Myc TF produced after hours
What do Th1 cells stimulate on B cells? 20
Stimulate Class II HLA and CD80 presentation on Th1 cells
What are the important functions of Th17? 22
Barrier function
Neutrophil activation
What diseases are Th17 associated with? 22
Associated with Multiple Sclerosis, IBD, and RA
What’s the main difference between bacterial superantigens and viral superantigens? 23
Viral superantigens are anchored into the APC membrane (DC)
Bacterial superantigens are soluble
What symptoms are associated with superantigens? 24
Turning on of T cells non-specifically
Fever & Rash
Edema
hypotension (TNF-α and IL-1 increase vascular permeability
Multiple organ failure and shock
What is one major difference between Effector T cells and resting naive T cells? 25
Effector T cell can respond to specific Ag w/o CD80-CD28 interaction
What three general tasks occur in the lymph node? 26
Ag recognition
Proliferation
Differentiation
How do Th cells migrate through the lymph node during resting and activation? 28
Activated by APCs in medullary area
CD4 T cells change chemokine expression allowing them to move to edge of follicular zone (down regulate-CCR7, upregulate-CXCR5)
During infection why will naive T cells float by an Ag site while effector T cells stop? 30
Effector T cells have changed their integrin expression and are able to adhere and stop at the Ag site while naive T cells have not change their expression
What cell is involved in intracellular parasite killing? 33
Cytotoxic Lymphocytes
What is the cluster differentiation for Fas? 34
CD95
Do CTL’s express Fas or FasL? 36
FasL - Fas ligand
What cells are involved in Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)? What is ADCC? 41
Target cell death via Ab IgG
NK cells Macrophages Neutrophils Eosinophils Monocytes (phagocytize in the blood)
What happens with T cells in chronic infection? 42
The T cell response eventually declines due to wearing out of the T cell and they begin to express CTLA-4
What cytokines do memory T cells require for survival? 45
IL-7
IL-15
What T cells can become memory T cells? 45
Both CD4 and CD8 can become memory
Why are memory T cells so quick to respond? 45
Because they only require HLA Class and not a co-stimulatory signal
What is the transcription factor for production of Tregs? 47
FoxP3
What will CTLA-4 (CD25) bind to?
B7-1/2 (CD80)
What is PD-1? What is it found on? 48
Found on T, B, and Myeloid cells
Causes negative regulation of T cells
How does Epstein-Barr virus (EBV) survive and evade our immune system? 49
Makes an analog of IL-10 to shut down surrounding immune response
