Term
| What is the MHC made up of? |
|
Definition
| -It is made up of peptides that are derived from self so that normal cells in the body will process self proteins through proteasome, and those proteins that go to ER, bind to MHC and are expressed in all cells that express that MHC. |
|
|
Term
| In thymus, do self-peptide molecules that are processed and presented on cell membrane surface have a foreign peptide? Foreign antigen is not instructive to adaptive immune system. |
|
Definition
| No, they do not have a foreign peptide. Foreign antigen is not instructive to adaptive immune system. |
|
|
Term
| If you lose the MHC peptide what will happen? |
|
Definition
-If you lose the peptide, you lose the MHC.
-It will either be internalized or shed or replaced with new MHCs. Turnover time is a few hours.
-New MHCs are constantly being produced and going to cell membrane surface with a different form of peptide. |
|
|
Term
| Is somatic hypermutation for b cell an antigen-dependent or an antigen-independent process? |
|
Definition
-antigen dependent.
-You must have signal 1 to trigger response, then you get t cell help and t cells provide factors for b cell to synthesize AID to undergo class switch and somatic hypermutation |
|
|
Term
| t cell receptor complex has 3 components |
|
Definition
1) zeta-zeta homodimer molecule,
2) CD3,
3) TcR (made up of alpha and beta chain) |
|
|
Term
| signal transduction molecules of t cells |
|
Definition
Zeta zeta homodimer and CD3
(transduce signal to cell nucleus for activation) |
|
|
Term
| signal transduction molecules of b cells |
|
Definition
Ig-alpha and Ig-beta
(transduce signal to the cell nucleus for activation) |
|
|
Term
| ITAM - (Immunoreceptor Tyrosine based activation motifs) |
|
Definition
| when cells undergo activation, there are certain kinase motifs that give rise to phosphorylation in the cytoplasmic domains of Ig-alpha, Ig-beta, zeta zeta, and CD3; this is very important bc it is the basis by which Ig-alpha, Ig-beta, zeta zeta, and CD3 begin to initiate the early stages of activation events. Once they get phosphorylated that changes their capacity to phosphorylate other molecules and this ultimately leads to nuclear changes that give rise to cell division, expression of cytokine genes, and other co-activation signals. |
|
|
Term
|
Definition
-a co-activation signal on the b cell
-In the same way that t cells have factors that allow for class switch recombination such as IL-4 for IgE , this is a soluble molecule that triggers b cell differentiation. |
|
|
Term
| T cells when they begin to undergo activation will initially make IL-2 receptor (for naïve cell). What 2 chains make up this receptor? |
|
Definition
1) beta chain
2) Common gamma chain. – expressed as a chain with a multitude of different cytokine receptors, not just for IL-2 |
|
|
Term
| when a t cell begins activation in presence of antigen and begins to make its own IL-2 , it will induce expression of a third chain. What is the name of that chain? |
|
Definition
|
|
Term
|
Definition
a potent t cell growth factor that converts a low affinity receptor to a high affinity receptor.
-it will induce the cell to undergo rapid cell division and activation |
|
|
Term
| When t cell gets fully activated, it makes CD40 ligand (inducible molecule). What does this induce? |
|
Definition
|
|
Term
| If you don’t express CD40 ligand, what happens? |
|
Definition
-you don’t have AID induction, thus:
- no class switch recombination
- no somatic hypermutation
- Bc you need CD40 from the b cell and CD40 ligand from the t cell |
|
|
Term
| What would happen if CD40 ligand was constitutively expressed on t cells? |
|
Definition
| Well if it interacts with CD40 on b cells in a constitutive way you could get activation of b cells that you wouldn’t want. You only want b cells to be activated after the t cell itself has been induced to undergo its own activation |
|
|
Term
| how do b cells get antigen? |
|
Definition
-through membrane immunoglobin.
-. They internalize some of that antigen and then the b cell presents some of that ag in the form of MHC. The b cell will undergo their own early stages of activation through Ig-alpha and Ig-beta (part of the b cell receptor complex). |
|
|
Term
| is CD40 inducible or constitutive? |
|
Definition
|
|
Term
| is CD40 ligand inducible or constitutive? |
|
Definition
|
|
Term
| If the t helper cell interacts in an antigen specific way between MHC class 2 and peptide, then what happens to CD40? |
|
Definition
| then CD40 gets upregulated, t cells themselves undergo rapid cell division , b cells undergo rapid cell division and then the t cells and b cells can interact between CD40 ligand and CD40. |
|
|
Term
| In parafollicular zone there are many _____ |
|
Definition
|
|
Term
| Interdigiting dendritic cells are in the ________ and they are antigen-processing cells |
|
Definition
|
|
Term
| What type of cell will go to parafollicular zone and activate t cells? |
|
Definition
|
|
