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16 Cards in this Set

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What is one of the major roles of Th1 cells and what does it facilitate?
To induce macrophage activation (producing INF-G)
These macs have receptors that bind to bacteria and facilitate
Phagocytosis
Destruction
Intracellular regulation
What is the result of the Macrophage activation/detruction of baceria via Th1 cells?
Antigen is processed and presented which end up on the surface via MHC Class II
Presents to CD4 which differentiate into Th1
Regulated by IL-2 and IFN-G
Once activated Th1 induce macrophages which causes increased expression of what?
Class II MHC
CD40
TNF R
B7
Upregulation of what will help will help CD4+ stick around?
Class II MHC
B7
CD40
What does B7 do?
Crital co-stimulatory molecule for helper cell activation (CD4+)
What two signals are required for macrophage activation?
IFN-Gamma, which is the primary signal made by Th1
CD40L, Secondasry signal which makes the cell responsive to IFN-Gamma
BUT activation can happen in absence of Th1 b/c other cells make IFN-G (NK cells)
A classic DTH test
The TB test
It is a type IV hypersensittivity rxn
DTH says there is T cell involved
Treatment with topical steroid sometimes antihistamine
What is a hallmark of chronic inflammation?
Perivascular mononuclear cell infiltration
Also a morphologu of DTH
When does granulomatous hypersensitivity occur?
When antigen is not cleared and persistant T cell w/release of cytokines
What T cell is antigen specifuc, MHC restricted?
CD8+ cytooxic cells
Activation requires antigen recognition and second signals which may be differnt then those of CD4+
What is the outcome for pts infected with mycobacterium in different balances of T cells
Th1 cells (more protective)the pt will have Tuburculoid leprosy
Defective Th1 or dominant Th2 (less protective) Pt. will have Lepromatous leprosy (high bacterial count)
What is the role of CD4+ in activating CD8+?
Full activation of CD8+ in CTL sometimes requires CD4+ "helper" by providing the SECOND signal
Varys with type of antigen exposure
Usually required for weak innate immune responses help CD8 to differentiate
How are NK cells recognized
By expression of CD 16, CD56 and CD3-
They are Large Granular Lymphocytes (LGL)
Well developed cytosol containing cytoxic elements
How NK cells recognize target cells
Activating Receptors: tell it what to kill, by looking at surface molecules for an INTRACELLULAR pathogen
Inhibitory Receptors- tell it to stop killing
NK cells preferentially lyse taget cells W/O MHC class I!
What will inhibit NK cells from killing?
KIR on NK celll surface when bound to MHC class I
Other ways NK cells can recognize their target cell
Through use of CD16