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T cell Act 2
Terms in this set (28)
What are the three steps for the mature naive t cell to become an effector t cell?
1. Activation-increased proliferation and increased survival
TCR-MCH signals cytokine signaling
2. Differentiation-Th-cell subtype; cytokine signaling
3. Cytokine expression- Cytokine expression
In T cell activation, what are two THINGS that only happen in this phase?
From the last lecture, what were the three required DC signals that promoted ROBUST activation?
1. Promotes clonal survival
1. THC-MHC binding
2. co-stimulation signaling
3. Cytokine signaling
After the T cell activates, the second phase is differentiation which develops into T cell subtypes. These T cell subtypes have distinct roles. What are the two types THINGS required for the cell to differentiate?
1. Cytokine signaling
2. Environmental cues
For cytotoxic cell differentiation, are there different subtypes of cytoxic cells?
No, false; there is no definitive evidence that there are different types of cytotoxic T cells
For T helper cell differentiation, how many different subtypes are there?
What is the specific key that direct the differentiation of Tcells? The thing that binds to PRRS which trigger cytokine profiles which then directs the differentiation of Th cells.
What are polarizing cytokines?
cytokines released after the PRR binds to the pathogen
They direct the differentiation of subtypes
What are factors that determine polarizing cytokines?
1. Pathogen type
2. APC cell type
3. Neighboring cell types
What activates master gene regulators?
A polarizing cytokine
What do the master gene regulators do?
Impact and direct the EFFECTOR cytokine profiles
Do each Th cell subtype secrete the same effector cytokines?
Polarizing cytokines-->Master regulator-->Effector cytokines
What are two processes that promote cell differentiation selection?
1. Positive feedback loop
2. Cross-initiation Inactivation
What is a positive feedback loop?
When the cell goes through its final differentiation, it sends downstream effector cells back towards the original to promote its own master gene activity.
How long is the T cell:APC engagement?
six to eight hours
What are the two type of Tc(CD8) cells?
What organs do they leave?
WHere do they circulate?
What do they engage?
How long do they live?
1. Tc effector cells-
Exit the 2o lymphoid organs
Circulate to the infection site
Engage and kill infected cells
Lifespan: few days to few weeks
2. Tc memory cells-
Lifespan: long-lived (years)
May proliferate to maintain population
What are the two types of Th effector(CD4)?
Whats the difference between the Tc(CD8)effector and Tc(CD4)effector?
1. Th effector cells
2. Th memory cells
The Th effector cells control other cells
What is homeostatic proliferation and what uses it?
Just a process where cells will create more of themselves to create a constant population; TH and TC memory cells
What is the difference between the primary response and secondary response for memory T cells?
A faster and more robust response in the secondary response
What are the differences between a memory cell and a naive cell?
Memory cells have a greater abundance and more widely distributed within the secondary lymphoid system. They are also present in circulation and tissues
Comparing the two G0 cycles between a memory cell and a naive cell, what is the difference between the activation periods between them?
Which activates with only dendritic cells?
Which activates with all apcs?
Where do they reside?
Memory cells can activate with all apcs while naive t cells can only activate with dendritic cells
Naive T cells are found only in the secondary lymphoid organs while memory cells can be found at even the infection sites.
What are the two types of memory cell subsets?
Which one has better functional efficiency?
Which one has longer life span?
1. Central memory
2. effector memory
For a normal activation, what is the total number of Th cells that respond to a regular toxin?
What about to a superantigen?
1 per 10,000 total Th cells
200 to 2,000 per 10,000
That is a massive response!
In a superantigen complex between a Th cell and an APC, what are the characteristics that is different from a regular peptide?
1. cross links the mhc and TCR
2. Mimics a strong TCR:MHC2 interaction
3. THERE IS NO AFFINITY for the bound protein needed
4. RESULTS IN ROBUST ACTIVATION OF T CELLS
What kind of proteins are exogenous superantigens?
What secretes these?
What kind of proteins are endogenous superantigens?
What secretes these?
1. Soluble proteins
Bacteria and a type of exotoxin
1. Integral member proteins
2. Coded by viral genes that have integrated into the host genome
What are a few consequences of superantigens to the body?
1. Clonal proliferation of T cells
2. Supresses adaptive immune system
3. large systemic release of cytokines
What are the possible contamination areas on the body or other area for toxin shock syndrome(staphalycoccus)
1. Skin lesions
2. sub cutaneous abcesses
3. Contaminated food
What was the problem with the super absorbent tampons in 1980?
They dried out the mucus, surface hydration, and anti microbials which allowed for easy growth of staphalycoccus
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