Flashcards in Imaging the Immune System in vivo Deck (46)
What techniques have been used to allow dynamic imaging of the immune cells in many tissues?
confocal and 2 photon microscopy intrsuments with new surgical methods and fluorscent labeling of cells
What is the main advantge of two-photon imaging?
gives ability to image depp into live tissues
What are the 3 structural families of adhesion molecules important for leukocyte recruitment?
selectins; integrins; Ig superfamily e.g ICAM
What do selectins bind?
What is the function of selectins?
intiate leukocyte-endothelial interaction
What are hte selectins expressed on endothelium?
P and E selectins
what is hte ligand for P and E selectins?
What do integrins bind?
cell-adhesion moleculesand ECM
give an example of an integrin?
Give an exmple of a ligand of LFA-1?
What is the function of integrins?
What cells is ICAM-1 found on?
activated endothelium and activated leukocytes
Waht type of protein are selectins?
What is found on the extracellular domain of ICAMs?
several Ig-like domains
What is the structure of an integrin molecule?
2 transmebrane protein chains alpha and beta
What other name is LFA-1 known as?
What other name is CR3 known as?
What may monocytes use to navigate out of hte blood vessel in the absence of infection?
ICAM-2 (expressed on resting endothelium)
What promotes strong adhesion between leukocytes and endothelial cells?
induction of ICAM-1 on activated endothelium and conformation change in LFA-1 and CR3
What is the function of integrins having an active and inactive state?
cells can make and break integrin0mediated adhesions in repsonse to signals received via the integrin or other receptors
What is the integrin molecule linked to the actin cytoskeleton when activated?
What is the function of talin?
chemokines generate intracellular signals that cause talin to the cytoplasmic tails of the beta chain of LFA-1 and CR3 forcing the extracellular region to become activated
What cytokine is especially important in activating endothelium?
how does TNF-a cause the appearnce of P-selectin?
induces the rapid externalisation of granules called Weibel-Palade bodies
How is E-selectin expresed on endothelial cells?
when P-selectin gets to the surface, mRNA encoding E-selectin is synthesis
What is the prominent leukocyte integrin on DCs?
CD11c:CD18 or CR4
How does the dilation of blood vessels initiate extravasation?
slower blood flow with dilation allowing leukocytes to interact with the vascular endothelium
What is the first stage of extravasation?
induction of selectins induces leukocyte rolling
What signals induce P-selectin appearance?
LT-B4; C5a; histamine; TNF-a and LPS