Term
| What do dendritic cells take up? |
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Definition
- they don't take up whole bacteria
- they take up bug bits that have been phagocytosed by neutrophils and macrophages |
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Term
| What happens first to bacteria bits taken up by dendritic cells? |
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Definition
| a vesicle called a phagosome is formed around the bits |
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Term
| What happens to the phagosome? |
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Definition
| a lysosome fuses with it to make a phagolysosome and enzymes within the lysosome break down the bits even more |
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Term
| TD4+ T cells recognize peptides in the context of ____. |
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Definition
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Term
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Definition
| Major histocompatibility complex |
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Term
| Antigens presented by the class II MHCs are derived from ____ proteins. |
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Definition
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Term
| Once bug bits are in the phagolysosome, and are degraded by enzymes, what happens? |
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Definition
| The phagolysosome merges with a vesicle that contains class II MHC. Peptide gets stuffed into the groove and then the vesicle merges with the membrane of the cell |
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Term
| What is the human equivalent of MHC? |
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Definition
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Term
| In the lymph node, what is step 1? |
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Definition
| Dendritic cells come to the node and present to T cells |
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Term
| Precursors to T lymphocytes leave the _ _ and are educated in the _. |
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Definition
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Term
| Describe antigen presentation to T cells by the dendritic cells. |
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Definition
- dendritic cell comes to the node and presents to every t cell until it find a match
- it can present to multiple at a time
- when it finds the right CD4+ T cell, the peptide in the groove of MHC binds to the T cell receptor
- BUT the T cell wants proof
- CD4 (on the surface of CD4+ T cell) binds directly to the class II MHC |
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Term
| Once the peptide (in context of class II MHC) binds to the CD4+ T cell receptor, and CD4 binds the Class II MHC, WHAT HAPPENS? |
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Definition
| The dendritic cell sends IL-12 saying - dude, we have an infection and I want you to do something about it |
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Term
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Definition
| co-stimulation involves interaction between the B7 receptor on the dendritic cell and the CD28 protein on the surface of the CD4+ T cell |
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Term
| Once the CD4+ T cell is activated, what happens next? |
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Definition
| Gene transcription of IL-2 and IL-2R |
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Term
| Explain T cell proliferation in response to T cell activation |
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Definition
1. Secretion of IL-2 happens
2. IL-2R get places on the surface of he T cell
3. IL-2 binds to the IL-2Rs and this causes proliferation! |
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Term
| Describe the nature of the proliferated T cells. |
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Definition
they are clones of each other!
But some will be memory cells and some will be effector cells |
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Term
| In the lymph node, what is step 2? |
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Definition
B cell and T cells interact.
Dendritic cells tell the T cell to leave the T cell area of the node and enter the B cell area to try to get B cells to create antibody.
Dendritic has also communicated with the B cells by releasing some antigen into the B cell area (bridging the T cell area and B cell area with long dendrites) |
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Term
| B cells take antigen in by _ _ _ not _. |
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Definition
| receptor mediated endocytosis, phagocytosis. |
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Term
| Describe receptor mediated endocytosis |
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Definition
A B cell has surface antibody that will bind soluble protein (that the dendritic cell released into the B cell area).
It then brings the soluble protein into an endosome, merges with a lysosome making an endolysosome, then it joins a vesicle with class II MHC, and soluble proteins gets stuffed into its groove....it's brought to the surface |
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Term
| Explain how T cells and B cells can recognize different things on the same molecule but still communicate with one another. |
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Definition
T cells recognize peptides and present them in class II MHC.
B cells can recognize the carb part of a glycoprotein (glycoprotein has a carb part and a protein part), and bring it in, but will then present the peptide part in Class II MHC in order to talk to T cells |
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Term
| If a CD4+ T cell is in the B cell area it is ___. |
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Definition
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Term
| In order to "help" the B cell, what does the CD4+ T cell do? |
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Definition
| it releases IL-4 and participates in co-stimulation |
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Term
| When the b cell clones itself, what happens?! |
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Definition
- every clone has the same antibody on its surface with same specificity as the original b cell
- the nodes get bigger because so many cells are in there |
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Term
| What types of b cell clones are made? |
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Definition
1. Memory B cells
2. B cells that differentiate into plasma cells |
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Term
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Definition
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Term
| Cells that are producing tons of protein have lots of __ __ |
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Definition
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Term
| What is the function of T cells sending cytokines to plasma cells? |
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Definition
| It tells the plasma cell what particular kind of antibody to make |
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Term
| Release of the IFN gamma cytokine leads to production of __ by plasma cells |
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Definition
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Term
| Release of the IL-4 cytokine leads to production of __ by plasma cells |
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Definition
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Term
| How does antibody get back to the site from the node? |
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Definition
it gets into the venous circulation and gets pumped around the body
- those spaces produced earlier allow the antibody to leak out into the site!! |
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