30 Questions
What is the major function of MHC?
To bind to processed antigen peptides and initiate an immune response
Which cells express MHC class II molecules?
Dendritic cells, Macrophages, B lymphocytes
How many major classes of membrane-bound glycoproteins are encoded by MHC?
Two
What does MHC stand for?
Major Histocompatability Complex
Which cells recognize MHC class I molecules?
CD8+ cytotoxic T cells (CTL)
What is the human equivalent of the Major Histocompatibility Complex?
Human Leukocyte Antigen (HLA)
What is the main function of MHC class I?
Binding and presenting endogenous antigens
Which cells function as antigen presenting cells (APC)?
Macrophages
What is the process of antigen presentation?
Displaying antigens within a cleft of an MHC molecule
Where are endogenous antigens degraded into peptides?
Cytosol
What is the role of transporters associated with antigen processing (TAP) molecules?
Pumping peptides from the cytosol into the endoplasmic reticulum
Which molecules release CLIP from the MHC molecule during antigen presentation?
HLA-DM
What is the function of HLA class II?
Binding and presenting exogenous antigens
What happens to exogenous antigens within the cell?
They are internalized and degraded within endocytic compartments
Which process involves cells moving from the blood vasculature to peripheral tissues?
Transmigration (diapedesis)
Which cell surface polypeptides ensure appropriate cell-cell interactions?
Mucin-like CAMs (Addressins)
What binds to CD34 and Glycam-1 (mucin-like) on endothelial cells?
L-selectin on leukocytes
Which molecules contain immunoglobulin-like domains and are expressed on endothelial cells?
ICAMs
What are the examples of Integrins that bind to Ig-superfamily CAMs?
LFA-1, Mac-1, and VLA-4
Which group of proteins bind selectins and are rich in serine and threonine?
Mucin-like CAMs (Addressins)
What is the process where leukocytes settle-out of the central flow column and 'marginate' along the endothelial surface?
Margination
What is the name of the complementary surface adhesion molecules briefly sticking and releasing, causing leukocyte tethering then rolling along the endothelium?
Selectins
What is the speed of tethering for leukocytes?
$400$ microns/sec
Which molecules participate in the adhesion by conformational changes to the integrin, allowing firm binding to Ig superfamily CAMs?
$ICAM-1$ and $VCAM-1$
During transmigration, cells must flatten and cross the endothelium basement membrane via:
Collagenases
What do leukocytes migrate towards by following a chemical gradient (chemokine) to the site of injury?
$Cytokines$ (e.g., $IL-8$)
What is the first step in lymphocyte migration?
$Rolling$
Which molecules can cause chemotaxis for leukocytes?
$Complement$ components ($C3a, C4a, and $C5a$)
What is shed during the rolling phase?
$Selectin$
What speed does rolling occur at?
$40$ microns/sec
Test your knowledge about the process of leukocyte migration from blood vasculature to peripheral tissues. This quiz covers events such as margining, tethering and rolling, activation, adhesion, transmigration (diapedesis), chemotaxis, and the role of cell-adhesion molecules.
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