Flashcards in Cells and Components of the Immune System Deck (37):
Which MHC class is recognized by Cytotoxic T Lymphocytes (CD8+)?
Which MHC class is recognized by Helper T Lymphocytes (CD4+)?
Do Natural Killer cells recognize MHC presentation?
No, but they recognize the Class I MHC as a "don't kill" signal
What do neutrophils do?
phagocytose bacteria coated with IgG and IgM
What do Mast Cells and Basophils release upon activation?
Where do immature T lymphocytes first enter the thymus?
Where are Hassall's Corpuscles located?
-medulla of the thymus
Where do lymphatics enter the lymph node?
on outer convex surface into subcapsular sinus
Where are HEV's located? What are they for?
-cortex of lymph nodes
-entrance point for lymphocytes
What is located at the center of a B nodule in a lymph node?
What makes up the buffy coat of blood?
What cells are leukocytes (white blood cells)?
What leukocytes are granulocytes?
What leukocytes are Agranulocytes?
What are the histological markers of neutrophils?
-three lobed nucleus
What are the functions of eosinophils?
-killer of parasites
-not phagocytic: they release their enzymes via exocytosis
-also modulate allergic inflammation to counteract histamine etc
What are the histological markers of lymphocytes?
-Large nucleus, a little bit bigger than RBCs
-Small amount of basophilic cytoplasm
What kind of surface marker (CD) is on B lymphocytes?
What kind of stem cell do eosinophils, basophils, neutrophils, monocytes, erythrocytes, and platelets derive from?
-Myeloid stem cell
What kind of stem cell do lymphocytes derive from?
-lymphoid stem cell
Which antibodies act as receptors on the surface of B Lymphocytes?
IgM & IgD
Humoral Immunity = ?
Antibodies & B Cells
Cellular Immunity = ?
What chemicals stimulate Cytotoxic T Lymphocytes to undergo clonal expansion?
What's the difference between basophils and mast cells?
Basophils are still circulating, mast cells are in tissue
What is the complement system?
-20 proteins that work together to destroy invaders
-humans born with defects in complement system don't live long
-Classical pathway depends on antibodies
Which protein initiates the "alternative" pathway for complement activation?
How do complement proteins eventually destroy bacteria?
-C3bBb cleaves more C3 as well as C5
-C5b, C6, C7, and C8 form a stalk that anchors the membrane attack complex (MAC) in the bacterial cell wall
-C9 comes along and makes a channel that opens a hole in the surface of the bacterium
Which proteins on human cells prevents complement from destroying friendlies?
-MCP (clips C3b)
-DAF (decay accelerating factor) (accelerates degradation of C3bBb)
What is a third complement activation pathway aside from the classical (antibody dependent) and alternative (antibody independent) pathways? What initiates this pathway?
-lectin activation pathway
-initiated by mannose-binding lectin (MBL)
What does iC3b do?
-cannot form Membrane Attack Complex (MAC)
-opsonizes invaders to facilitate phagocytosis by macrophages
How do natural killer cells kill cells?
-induce apoptosis via an injection system
-introduce granzyme B into target cell
-NK cell interacts with Fas on surface of target, inducing apoptosis
Where are proteins of the complement system produced?
**think about cirrhosis
What protein does C3bBb cleave?
What does the MASP protein do in the lectin activation pathway?
What do C3a and C5a do?
-act as chemoattractants to attract more macrophages and neutrophils