Linking Innate and Adaptive Immunity 2 Flashcards
do DCs only present 1 antigen?
no, they can present multiple antigens at once, multiple parts of an antigen
what is the role of selectins? what type of molecule is it?
selectins are responsible for binding and rolling of T cells
what do chemokines bind to? what type of chemokine?
CCL21 chemokine activates CCR7 receptor on lymphocyte
what happens once CCL21 binds CCR7 on lymphocyte?
CCR7 receptor is activated so lymphocytes can make integrins
what is the role of integrin? what type of molecule is it?
integrins are responsible for tight binding that causes the lymphocyte to migrate
what allows T cells to roll along endothelial surface?
light attachment of SELECTIN on T cells to ENDOTHELIAL CELLS of HEV
what vessel carries T cells to lymph nodes?
HEV
what vessel carries T cells to Peyer’s patch?
mucosal epithelium
what is the main, general role of selectins?
“leukocyte homing”
aka bind receptors to target T cells to lymphoid tissue
what are the 4 steps of lymphocyte migration? and the molecules involved?
- ROLLING –> selectins at HEV allow lymphocyte to roll along endothelium
- ACTIVATION –> CCL21 secreted by HEV binds CCR7 and leads to conformation change in integrin
- ARREST + ADHESION –> integrin changes conformation to bind ICAM and keep lymphocyte in one place
- DIAPEDESIS –> lymphocyte migrates across endothelium
how do DCs attract T cells to them? where does this occur?
in the lymph node, DCs secrete chemokines to attract T cells to them
what is the function of fibroblastic reticular cells? where is it located?
make a mesh surrounding lymph node
they secrete CCL21 chemokines which attract T cells and DCs to lymph nodes
what happens to the movement of naive T cells before and after they bind the DC?
before: T cells move around a lot
after: T cells stop moving once antigen binds MHC on DC
what does the interaction of T cells with the antigen depend on? (4)
- quality of antigen
- quantity of antigen
- availability of antigen
- activation state of DC
how long do T cells bind to DCs?
> 8h