T Cell Activation

Start Studying!

Terms

undefined, object

copy deck

What is the TCR\'s basic function?: To sense what is going on the outside of the cell.
Name the two types of TCR\'s: Alpha/Beta & Gamma/Delta
How are TCR proteins assembled?: By mixing and matching gene segments.
The mixing and matching of gene segmentds, is similar to what other cell\'s mixing and matching of what?: Heavy and light chains of B Cells
In T & B cell what proteins initiate splicing of gene segments?: RAG1 & RAG2
What do RAG1 & 2 proteins do in T & B cells?: Initiate splicing of gene segments by making double stranded breaks in chromosomal DNA
What happens when RAG1 & 2 proteins create a double stranded break in chromosomal DNA in T & B cells?: It initiates gene segment splicing.
Can TCR\'s have both pair of proteins?: No
95% of T cells circulating the blood have gamma/delta TCR\'s: False, 95% of circulating T cells, TCR\'s are alpha/beta
95% of TCR\'s express what co receptors?: CD4 or CD8
What TCR don\'t express CD4 or CD8?: gamma/delta TCR
Where are T cells with gamma/delta TCR\'s most abundant in?: Intestine, uterus and tongue; which come in contact with the outside world.
Where are gamma/delta T cells found in mice?: Epidermal layer of the skin.
Are T cells found in the epidermal layer of the skin in humans?: No
Which pair of receptors are the least diverse?: Gamma/Delta
Where are gamma/delta T cells educated?: It\'s unknown
Where are alpha/beta T cells educated?: The thymus
What are gamma/delta T cells taught in the thymus?: They aren\'t taught at the thymus because it is not known where they are educated.
What are alpha/beta T cells taught in the thymus?: Not to react against our own self peptides.
What do gamma/delta T cells recognize?: It\'s unknown
What do some gamma/delta T cells do?: They kill cells that become stressed, due to a bacterial infection.
What does a TCR recognize outside of the cell?: MHC peptide complex
What classes of MHC molecules are there?: MHC1 & MHC2
How many MHC molecules does a t cell recognize?: only one
After a TCR recognizes its cognate antigen presented by an MHC molecule, what is the next step for the tcell: To transmit a signal from the surface of the tcell, to the nucleus.
What must happen in the nucleus for the tcell to be activated?: Gene expression must be altered
What does the external part of the transmembrane do?: It binds to a molecule called the ligand, outside the cell.
What does the internal part of the transmembrane do?: It initiates a biochemical cascade, that conveys a ligand bound signal to the nucleus
What is the ligand made out of?: MHC molecule and peptide
How long are the cytoplasmic tails of alpha/beta?: 3 amino acids long
What proteins is CD3 made out of?: gamma,delta,epsilon & zeta
Where are the CD3 proteins located?: Anchored in the cell membrane.
How does a tcell get a strong signal to the nucleus?: clustering of receptors
What is recruited by the cytoplasmic tails of the CD3?: Kinase enzymes
Name all the proteins involved in the tcell,: alpha, beta, gamma, delta, epsilon, & zeta
What is the first step in t cell signaling?: All the proteins are transported to the surface of the cell
Alpha/Beta are great for?: Recognition
Alpha/Beta suck at?: Signaling
Gamma/Delta/Epsilon/Zeta are good at?: Signalig
Gamma/Delta/Epsilon/Zeta signal fine bur?: They are blind as to what is happening outside of the cell
During their education in the thymus, TCR are used to trigger?: Suicide by apoptosis
If the TCR recognizes MHC plus self peptides, what happens?: TCR trigger suicide(by apoptosis)
What happens if the TCR recognizes their cognate antigen presented by MHC molecule, but not the co-stimulatory signal?: The cell is anergized
What two things must happen in order for the T cell to activate?: It must recognize its cognate antigen and receive co-stimulatory signals
Killer T cells attach to what MHC molecule: MHC1
Helper T cell attach to what MHC molecule?: MHC2
Name 3 APCs: Dendritic cells, macrophage and B cells
Killer T cells express what co-receptor: CD8
Helper T cells express what co-receptor: CD4
What molecule does CD8 clip on to?: Class 1 MHC
What molecule does CD4 clip on to?: Class 2 MHC
Class 1 MHC clips on to?: CD8
Class 2 MHC clips on to?: CD4
What connects a MHC molecule to a TCR?: Peptides
What strengthens the adhesion between T cell and APC?: MHC molecules and CD4&8 co-receptors
CD4&8 function is to?: Focus the attention of Killer T cells and Helper t cells on the proper MHC molecule
CD4 is composed of how many proteins?: ONE
CD8 is composed of how many proteins?: TWO
How are CD4&8 glued to the tcell?: Loosely
When is the only time that the T cell expresses CD4 & 8 plus?: When it\'s maturing in the thymus
When the T cell is maturing in the thymus what does it express?: Both CD4 & 8 plus
How does the t cell decide which co receptor it will express?: unknown
What makes the signal from the membrane to the nucleus 100x stronger?: Co-stimulatory signal
T cells have a reduced requirement for co stimulation: True
Rafts on top of the t cell are made out of?: cholesterol
What do these \"rafts\" found on the top of t cells do?: They carry signals to the nucleus, when TCRs are engaged
What\'s the function of rafts in naive t cells?: None
When to TCRs and rafts come together?: When the TCRs engage with the cognate antigen
Where are rafts stored in naive tcells?: Inside the cell as other membranous parts
Why is it thought that the connection between TCRs and the nucleus isn\'t very strong in virgin tcells?: Lack of rafts
What is the other name of downstream signaling molecules?: rafts
When is it thought that the rafts are rushed to the surface?: when the tcrs engage to the cognate antigen and the application of co-stimulation
What is the job of rafts on top of mature tcells?: Carry signals
Name two co-stimulators of tcells: B7-1 & 2 proteins
Where are B7 proteins found?: On the surface of antigen presenting cells
How do B7 proteins provide co-stimulation?: By plugging into the receptors on the t cells surface
Name the two receptors that B7 proteins plug into on the tcell: CD28 & CTLA-4
When is CTLA-4 molecules expressed?: When the tcell has been activated
B7 proteins on APCs do what on virgin tcells?: Tie up the CD28 receptors, thereby providing a co-stimulatory signal for activation.
How do t cells turn off?: Ligation of CTLA-4 receptors by B7 proteins
T cells are part of what immune system?: Adaptive
Why is it important for the adaptive immune system to turn off?: So that B & T cells protect us against present and future invaders.

Start Studying!

Deck Info

Number of cards 82

Created By sammy1194