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16 Cards in this Set
- Front
- Back
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What is one of the major roles of Th1 cells and what does it facilitate?
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To induce macrophage activation (producing INF-G)
These macs have receptors that bind to bacteria and facilitate Phagocytosis Destruction Intracellular regulation |
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What is the result of the Macrophage activation/detruction of baceria via Th1 cells?
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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 |
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Once activated Th1 induce macrophages which causes increased expression of what?
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Class II MHC
CD40 TNF R B7 |
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Upregulation of what will help will help CD4+ stick around?
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Class II MHC
B7 CD40 |
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What does B7 do?
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Crital co-stimulatory molecule for helper cell activation (CD4+)
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What two signals are required for macrophage activation?
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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) |
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A classic DTH test
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The TB test
It is a type IV hypersensittivity rxn DTH says there is T cell involved Treatment with topical steroid sometimes antihistamine |
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What is a hallmark of chronic inflammation?
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Perivascular mononuclear cell infiltration
Also a morphologu of DTH |
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When does granulomatous hypersensitivity occur?
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When antigen is not cleared and persistant T cell w/release of cytokines
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What T cell is antigen specifuc, MHC restricted?
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CD8+ cytooxic cells
Activation requires antigen recognition and second signals which may be differnt then those of CD4+ |
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What is the outcome for pts infected with mycobacterium in different balances of T cells
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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) |
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What is the role of CD4+ in activating CD8+?
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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 |
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How are NK cells recognized
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By expression of CD 16, CD56 and CD3-
They are Large Granular Lymphocytes (LGL) Well developed cytosol containing cytoxic elements |
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How NK cells recognize target cells
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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! |
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What will inhibit NK cells from killing?
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KIR on NK celll surface when bound to MHC class I
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Other ways NK cells can recognize their target cell
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Through use of CD16
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