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42 Cards in this Set
- Front
- Back
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What are the 3 ways a pathogen can harm a cell?
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Exotoxin, endotoxins, direct cytopathic effect
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What are some extracellular defences?
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Complement macrophage neutrophils, antimicrobial peptides
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Intercellular defences?
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NK cells, activated macrophages
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Cleavage of C3 exposes what?
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Reactive thioester bond (nucleophile)
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What is the alternative pathway?
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Pathogen surface creates local environment conducive to complement activation
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Defensins are ....
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Variable antimicrobial peptides
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What is the lectin pathway
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Mannose binding lectin binds to pathogen surface
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Classical pathway
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C-reactive protein of antibody binds to specific antigen on the pathogen surface
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After cleavage if c3 to c3a and c3b, what are the three things that can occur to neutralize the pathogen?
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1. Recruitment of inflammatory cells, 2. Opsonization of pathogens, facilitating uptake and killing by phagocytes, 3. Perforation of pathogen cell membranes
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What does properdin do?
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Stabilizes C3 convertase C3bBb on the pathogen surface
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What does factor H/I do?
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Inactivates C3b fragments
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What two factors are required for C3 inactivation on a pathogen surface?
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DAF (decay accelerating factor) & MCP (membrane cofactor protein)
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What are MACs? What complements are involved?
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Proteins that create lesions in the pathogen membrane. C5b, C6, C7, C8, C9
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What do C3a and C5a induce?
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Local inflammation
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What is the relationship between protease and alpha2-macroglobulin?
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alpha2-macroglobulin creates a trap with bait to lure protease into it
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What do TLRs do?
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Sense infections in and outside of the cell
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What is the function of NFkB?
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Initiates transcription of inflammatory cytokines. They are synthesized in the cytoplasm and secretes via the ER
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Activation of TLRs leads to two different pathways which are....
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1. Synthesis & secretion of type 1 interferons (IFN-alpha & IFN-beta) 2. Synthesis and secretion of TNF-alpha & other inflammatory cytokines
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What are the pro-inflammatory cytokines secreted by macrophages??
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IL-6, TNF-alpha, IL-1B, CXCL8, and IL-12
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What does TNF-alpha do?
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Induces leakage
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What does TNF-alpha do?
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Induces leakage
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What do chemokines bind to?
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GPCRs
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What does TNF-alpha do?
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Induces leakage
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What do chemokines bind to?
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GPCRs
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What happens when a chemokine binds to a GPCR?
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GTP replaces GDP & activates the G protein
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What does the G protein do?
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Activated pathways of signal transduction
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What are the 4 types of adhesion molecules?
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CD34, Selectin, integrin (LFA-1), ICAM-1
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What are the 4 types of adhesion molecules?
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CD34, Selectin, integrin (LFA-1), ICAM-1
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What's the livers function in regards to innate immunity?
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Activation of complement optimization
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What are the 4 types of adhesion molecules?
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CD34, Selectin, integrin (LFA-1), ICAM-1
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What's the livers function in regards to innate immunity?
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Activation of complement optimization
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What's the bone marrow endotheliums function in regards to innate immunity?
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Phagocytosis
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What are the 4 types of adhesion molecules?
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CD34, Selectin, integrin (LFA-1), ICAM-1
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What's the livers function in regards to innate immunity?
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Activation of complement optimization
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What's the bone marrow endotheliums function in regards to innate immunity?
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Phagocytosis
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What's the hypothalamus & fat/muscles function in regards to innate immunity?
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Decreased viral & bacterial replication
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What's the difference between Mannose-lectin binding and C-reactive protein binding when it comes to opsonization?
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C-reactive protein binds to phosphocholine on the bacterial surface, whereas mannose binding lectin binds to carbohydrates on the bacterial surface
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Describe the steps involved in the classical pathway
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1. MASP-2 cleaves C4 into C4a & C4b (which binds to the pathogen surface). 2. MASP-2 cleaves C2 into C2a & C2b. 3. C2a binds to the C4b forming C4b2a. 4. C4b2a binds to C3 & cleaves it into C3a & C3b. C3b binds to microbial surface
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What does binding of C1 to the C-reactive protein activate?
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Classical pathway of complement fixation
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Cells infected with viruses produce ____ Interferons
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Type 1
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What are the 3 interferon responses?
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1. Resistance to viral replication 2. Increased expression of ligand receptors on NK cells
3. Activate NK cells |
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IFN-y is an example of what? What is it's importance?
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Type 2 interferon produced by NK cells. It activates macrophages to secrete cytokines which help activate tcells (ie. The adaptive immune response)
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