Flashcards in Cell Immunity 1 Deck (26):
name given to a family of pro-inflammatory activation- inducible cytokines?
chemokines----> induce chemotaxis
Chemokines are divided into families based on what?
relative positions of TWO highly conserved CYSTEINE residues at the AMINO terminal
Are there any chemokines that lack the first conserved cysteine?
Yes, two XCL1 and XCL2
Chemokines acton a family of 18 receptors….all of which are in what class?
What does large number of chemokines and chemokine receptors available to the immune system provide?
precise control over inflammation (attract different subsets of immune cells)
What are the only type of cells that can extravasate through HEV?
Lymphocytes----most DC's enter through afferent lymphatics
Movement of lymphocytes throughout the body is controlled by what three molecules?
selectins, chemokines, and integrins
Selectins are important for what ?
Integrins are important for what in migration?
What selectin is expressed on lymphocytes, especially naive t cells before they have been activate?
L-selectin---also on monocytes and neutrophils
What is the ligand for E-selectin that is expressed on endothelial cells?
sialylated carbohydrates on many different immune cells
What selectin binds to glycoprotein ligand on leukocytes, heparan sulfate, and fucoidan?
P-selectin on endothelial cells
T - F selectins bind many proteins binding N-linked carbohydrate chains?
are integrins made up of homodimers or heterodimers?
heterodimers one of each 18 alpha and 8 beta chain---24 unique integrins
What needs to happen for the integrin to be activated and bind with higher affinity?
TCR stimulation or chemokine receptor stimulation that results in conformational change of the integrin
HEV produce what chemokine?
Stromal cells around HEVS secrete what chemokine?
What does L-selectin bind?
CD34, GlyCAM-1, PNAd on peripheral lymphnode
MAdCAM-1 on mucosal lymphoid tissue
Naive T cells exit is controlled by a gradient of what?
S1P-sphingosine 1-phosphate- activated receptor on T cell causes it to leave lymph and enter blood or lymph duct....if it is activated in the lymph node it will downregulate its receptor in order to stay there
What keeps concentration of S!P low?
S1P lyase in lymphoid and peripheral tissues
What chemokine receptor do immature dendritic cells express for migration into peripheral tissues?
T-F naive T cells specific to a particular antigen are common?
False---they are very rare
What 3 signals do Naive T cells receive 3 signals from an activated antigen-presenting cell?
1: recognition of peptide bound to MHC by TCR
3: cytokines direct the differentiation of CD4 T cells into numerous effector subsets and direct CD8 T cells to acquire effector functions
What receptor is crucial for cell expansion that follows the activation of a naive T cell?
IL-2 receptor (CD25) drives expansion (binds IL-2 ligand)
What promotes S1P receptor degradation?
CD69--a C-type lectin recepor
---TCR stimulation also down regulates this protein. Botha cations leads activated T cells to be detained in the LN