part 9

Question 1

what are the most important APCs

Answer 1

DCs, macrophages, and B cells

Question 2

why are DCs, macros, and B cells the most important APCs

Answer 2

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).

Question 3

what do Langerhan cells do during an infection

Answer 3

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.

Question 4

what does B7.1 bind to

Answer 4

CD80

Question 5

what does B7.2 bind to

Answer 5

CD86

Question 6

CD80 and CD86 function

Answer 6

providing costimulation to T cells via ligation of CD28. Both ligands can also bind to the inhibitory receptor CTLA-4.

Question 7

what cytokines are released during T cell activation

Answer 7

IL-4, -6, -23
TNF alpha

Question 8

what can CD4 regulatory cells do

Answer 8

shut down immune responses

Question 9

how does CD4 regulatory shut down immune responses

Answer 9

Secretes IL-10, which is the IL that shuts off immune responses when secreted.

Question 10

what are HEVs

Answer 10

high endothelial venules, found in the paracortical region

Question 11

what is the function of HEVs

Answer 11

allow circulation of naive T cells in to the lymph node/PR
T cells cross over the HEV in the lymph node by diapedesis.

Question 12

what are some properties of HEVs

Answer 12

HEVs have ICAMs, addressins, and other receptors that attract T cells to the venule.

Question 13

what does clonal selection lead to

Answer 13

proliferation

Question 14

what are the different types of T cells

Answer 14

effector cells, memory cells, or regulatory cells.

Question 15

what does clonal differentiation mean

Answer 15

specialization

Question 16

what are the two types of memory T cells

Answer 16

central and effector

Question 17

how are T cells distinguished

Answer 17

by their protein features/specific versions of proteins

Question 18

what are anergenic T cells

Answer 18

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

Question 19

what are exhausted T cells

Answer 19

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.

Question 20

what APC lives in the medullary region

Answer 20

macrophages

Question 21

what APC lives in the germinal center

Answer 21

B cells

Question 22

what APC lives in the paracortical region

Answer 22

T cells

Question 23

how do DCs effect the lymph node

Answer 23

Dendritic cells can enter the paracortical region and come into contact with T cells there.

Question 24

what happens if T cells aren’t being circulated through the lymph node

Answer 24

they are circulated elsewhere

Question 25

what happens when T cells are activated by dendritic cells

Answer 25

the T cells stay in the lymph node

Question 26

When leukocytes migrate to the infected site they express

Answer 26

P-selectin
2 hours later, p-selectin is switched to E-selectin
Then integrins are expressed.

Question 27

what is L-selectin expressed by

Answer 27

naive T cells

Question 28

what is secreted during the rolling phase

Answer 28

selectins (L-selectin)

Question 29

what is secreted during activation phase

Answer 29

chemokines (CCL21)

Question 30

what is secreted during adhesion phase

Answer 30

integrins (LFA1)

Question 31

what is secreted during diapedisis

Answer 31

chemokines (CCL-21 and CXL-12)

Question 32

what is Sialyl-Lewis

Answer 32

a sugar bounded by L-selectin

Question 33

what is the function of Sialyl-Lewis

Answer 33

mediate adhesion between tumor cells and endothelium by interacting with its selectin ligands.