part 9 Flashcards
what are the most important APCs
DCs, macrophages, and B cells
why are DCs, macros, and B cells the most important APCs
because they express a high amount of CD80 and 86
Best at stimulating naive T cells (T cells that have never come into contact with an antigen before).
what do Langerhan cells do during an infection
Langerhan cells release cytokines/chemokines, which allow inflammation, which causes migration of lymphocytes (neutrophils) from the blood vessel to the site of infection/cut.
Swelling is caused by edema/lymph.
Selectins to integrins, which bind to ICAMs.
what does B7.1 bind to
CD80
what does B7.2 bind to
CD86
CD80 and CD86 function
providing costimulation to T cells via ligation of CD28. Both ligands can also bind to the inhibitory receptor CTLA-4.
what cytokines are released during T cell activation
IL-4, -6, -23
TNF alpha
what can CD4 regulatory cells do
shut down immune responses
how does CD4 regulatory shut down immune responses
Secretes IL-10, which is the IL that shuts off immune responses when secreted.
what are HEVs
high endothelial venules, found in the paracortical region
what is the function of HEVs
allow circulation of naive T cells in to the lymph node/PR
T cells cross over the HEV in the lymph node by diapedesis.
what are some properties of HEVs
HEVs have ICAMs, addressins, and other receptors that attract T cells to the venule.
what does clonal selection lead to
proliferation
what are the different types of T cells
effector cells, memory cells, or regulatory cells.
what does clonal differentiation mean
specialization
what are the two types of memory T cells
central and effector
how are T cells distinguished
by their protein features/specific versions of proteins
what are anergenic T cells
T cell is stimulated, but not stimulated enough:
No C28 co-stimulation, therefore non-functional.
If it isn’t stimulated properly for long enough, the cell dies
what are exhausted T cells
old T cells that have undergone many rounds of proliferation and can no longer proliferate.
If too many exhausted T cells, the immune system is not as efficient.
what APC lives in the medullary region
macrophages
what APC lives in the germinal center
B cells
what APC lives in the paracortical region
T cells
how do DCs effect the lymph node
Dendritic cells can enter the paracortical region and come into contact with T cells there.
what happens if T cells aren’t being circulated through the lymph node
they are circulated elsewhere
what happens when T cells are activated by dendritic cells
the T cells stay in the lymph node
When leukocytes migrate to the infected site they express
P-selectin
2 hours later, p-selectin is switched to E-selectin
Then integrins are expressed.
what is L-selectin expressed by
naive T cells
what is secreted during the rolling phase
selectins (L-selectin)
what is secreted during activation phase
chemokines (CCL21)
what is secreted during adhesion phase
integrins (LFA1)
what is secreted during diapedisis
chemokines (CCL-21 and CXL-12)
what is Sialyl-Lewis
a sugar bounded by L-selectin
what is the function of Sialyl-Lewis
mediate adhesion between tumor cells and endothelium by interacting with its selectin ligands.
