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32 Cards in this Set
- Front
- Back
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CTLA-4 and B& on APC
function dysfunction |
competes with B7 for binding to CD28 which is on Thelper cells.
B7 activates CTLA-4 inactivates. |
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explain costimulatory signal
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Bcells express B7 which binds to Thelper cells CD28 and activates a cell signalling cascade inside the Tcells.
THIS IS SIGNAL NUMBER 2 for TCell activation |
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why would a Tcell go into anergy?
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if it recieved the signal #1 of antigen binding to the TCR, but did NOT recieve the costimulatory signal of B7 binding to CD28
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Th1 population responsible for
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cell-mediated functions like delayed type hypersensitivity, activating CD8+ TC cells
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what do Th1 cells secrete?
(cytokines) |
IL-2, IFN-gamma, and TNF-beta
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what do Th2 cells secrete?
(cytokines) |
IL4,
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what do the Th2 cytokines activate?
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bcells and humoral response
IL4 |
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what two cytokines have a systemic effect, and through what type of signalling
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endocrine signalling; TNF and IL-1
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WHAT is the effect of systemic cytokines, which are they
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fever, inflammation, induction of acute phase proteins; TNF alpha and IL-1
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function of IL-4
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forms IgE by affecting DNA looping in gene expression
enhances mast cell proliferation |
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INF-gamma function
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increase expression of MHC 1 and 2
interferon by the way |
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4 classes of cytokines in alphabetical order:
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Chemokines
HEmatopoietic Interferons Tumor necrosis factor |
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function of chemokines
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acctract cells to inflammatory site; leukocyte trafficking
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function of hematopoietins
3 example cells |
blood cell production/regulation of amounts; erythropoietin, IL-2 and CSF (colony stim factor)
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function of IL-2, what type of cytokine it is
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hematopoietic; produced by Thelpers when interacting with APC; signal #3 for Bcells
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Function of Il-4, what type of cytokine it is;
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hematopoietic; promotes class switching to IgE - allergy, mast cells, basophils
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function of CSF, what type of ctokine
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hematopoietic; determines myeloid or lymphoid progenitor pathway
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all interferons are:
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ANTIVIRAL; respond to virus infection by encouraging MHC 1 and 2 expression; enhance degrading of viral material, activate NK and Tc cells (alpha/beta)
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function of TNF cytokines
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similar to fas, they induce cell death - have a SYSTEMIC EFFECT (along with IL-1)
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how do molecules antagonize cytokines?
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by mimicking the actual cytokines and binding to their receptors so the cytokines cant;
by mimicking the receptors of cytokines so the cytokines bind to the wrong thing. |
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All Th2 cytokines are:
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INTERLUEKINS!!! IL IL IL IL IL IL
except for GM-CSF |
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Th1 subset particularly suited to:
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viral infections
intracellular antigens/pathogens |
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which interleukin is essential for generation of Th2 response?
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IL-4
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WHAT IS crossregulation of cytokines?
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each subset inhibits the development of the other; thus the critical molecules that start development down a particular pathway (IL4 and INF-gamma)
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which is better, tuberculoid or lepromatous leprosy?
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tuberculoid; a cell-mediated immune response can take place because the Th1 cytokine population is increased. in lepramatous, Th2 are there and antibodies are not antiviral like cell-mediated Tkilling cells
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what type of cytokine-related disease results from ENDOTOXINS
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endotoxins from bacteria cell wall
SEPTIC SHOCK from systemic overproduction of TNF alpha and IL-1 |
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2 primary producers of cytokines
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macrophages
Thelper cells |
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how cytokines modulate/enhance
-Innate immunity -Adaptive immunity |
innate: chemokines attract cells to inflammatory site; ENHANCED VASODILATION
adaptive: activate b or t cells; modulate blood cell population |
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what is a cytokine?
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a small protein that communicates effects in the immune response
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what are 5 attributes of cytokines?
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pleiotropy
synergy antagonism redundancy cascade induction |
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what are the 2 subunits of a cytokine receptor?
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-ligand binding subunit
-signal transducing subunit |
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what is an example of cytokine receptor?
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IL-2Receptor; has alpha, beta, and gamma subunits;
gamma/beta are constitutive, but alpha only expressed on Ag-activated Tcells. result: high-affinity binding of cytokine IL-2 only when needed. |
