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82 Cards in this Set
- Front
- Back
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What innate immune cells are the major defense against pyogenic bacteria?
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Neutrophils
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What innate immune cells combat bacteria, viruses, and protozoa that can live within cells?
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Macrophages
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How do innate immune cells recognize pathogens?
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By PRRs which see PAMPs on the microbes.
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What is an example of a PRR?
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TLR
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What is the function of TLRs?
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To promote adherence and send danger signals that induce phagocytosis.
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What system is used to attract phagocytic cells to microbes?
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Complement
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What does complement achieve?
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Opsonization
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What are the 3 cells that are major players in innate immunity?
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-neutrophils
-macrophages -NK cells |
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What are NK cells specialized for killing?
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-Virally infected cells
-Tumor cells |
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How do NK cells interact with other cells?
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By 2-signal interactions
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What are the 2 receptor interations that NK cells use to engage with viral or tumor cells?
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-Cell surface recognition receptors
-MHC1/KIR interaction |
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What is a KIR?
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Killer inhibitory receptor
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What happens when the KIR binds a cell with class I MHC?
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The killer cell can't kill it because it is inhibited.
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What happens when an NK cell's KIR does NOT bind an MHC I?
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The NK cell can kill that cell that it is seeing because it lacks the inhibitory signal.
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What is the other method of killing that NK cells utilize?
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ADCC
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What are the 3 components of adaptive immunity?
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-Antibodies
-Tcells -Bcells |
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What is the special feature that sets adaptive immunity apart?
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Memory
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What is an antigen?
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A molecule that stimulates an immune response
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What is an epitope?
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The smallest part of an antigen that can evoke an immune response.
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What are the sentinels of the immune system?
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Dendritic cells
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What are dendritic cells in the skin called?
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Langerhan's cells
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What does binding of antigen to immature dendritic cells cause?
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Upregulation of Class II MHC
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What happens after dendritic cell binding of antigen and upregulation of MHC II?
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The complex migrates to the nearest lymph node to present the Ag/MHCII to Tcells.
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What are the 2 components of adaptive immunity that are activated by antigen presentation in lymph nodes?
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-Humoral immunity
-Cellular immunity |
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Humoral immunity functions against:
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Extracellular microbes
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Cellular immunity functions against:
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Intracellular microbes
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How do antibodies kill pathogens?
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By marking them for destruction by the innate immune system.
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What does the Bcell receptor complex consist of?
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-Membrane bound Ig
-Signal transduction molecules |
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What are the 3 signal trnasduction molecules on the BCR complex?
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-Igalpha
-Igbeta -CD21 |
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How is BCR diversity generated?
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By genetic recombinations.
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How is TCR diversity generated?
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By genetic rearrangements also
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What are the 3 signal transduction molecules in the TCR complex?
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CD3
zeta CD28 |
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What cytokines promote leukocyte recruitment and acute inflammatory responses?
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IL1 and TNF
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What cytokine activates Tcells by binding to autologous receptors?
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IL-2
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What cytokine activates eosinophils?
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IL5
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What cytokine activates macrophages?
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IFN-y
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What cells are susceptible to EBV infection?
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Bcells
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What receptor is used by EBV to infect Bcells? What is the normal function of this receptor?
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CD21 - the complement receptor (signal transduction molecule?)
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What does the Bcell do once infected with EBV?
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Presents chopped up peptides on Class II MHC to Thelper cells.
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What is the Thelper response to antigen presentation by Bcells?
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Secretion of cytokines which stimulate CTL proliferation to attack the virally infected bcells.
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What is the characteristic Type I HSN reaction?
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Allergy
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What is the cause of allergy?
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Overactivation of Th2 cells and IgE antibody production
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What are genetically determined high levels of IgE called?
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Atopy
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What are the steps in Type I HSN?
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-Allergen presented by DCs
-TH2 response secretes IL4,5,10 -IgE is secreted and coats mast cells -Subsequent exposure causes mast cell degranulation |
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What are the 4 physiologic responses to mast cell release of primary and secondary mediators?
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1. Smooth muscle spasm
2. Blood vessel dilation 3. Leukocyte infiltration 4. Mucus secretion |
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What are the 2 classic examples of Type I HSN?
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1. Bronchial asthma
2. Systemic anaphylaxis |
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What is the cause of mucus secretion in bronchial asthma?
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The late phase reaction caused by infiltrating neutrophils and eosinophils.
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What are the 2 main treatments for bronchial asthma? What is each prescribed for?
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1. Corticosteroids - to reduce inflammation
2. PDE inhibitors - to relax the bronchial smooth muscle |
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What is the major initiating event of an acute allergic reaction?
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Mast cell degranulation
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What are the 2 major effects of Histamine?
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-Smooth muscle contraction
-Vascular dilation |
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What effect do proteases and prostaglandins and leukotrienes have?
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Protease: tissue damage
Prostaglandin: vascular dilation Leukotrienes: smooth muscle contraction |
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What is responsible for the late phase reaction of leukocyte recruitment?
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Cytokines
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What are the primary mediators in mast cell granules?
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-Histamine
-Proteases -Chemotactic factors |
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What are the secondary mediators in mast cells?
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-Cytokines
-Eicosanoids |
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What are the 2 products of arachidonic acid metabolism?
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-Prostaglandins
-Leukotrienes |
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What is the source of arachidonic acid?
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Membrane phospholipid cleavage by Phospholipase A2
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What additional 2ndary mediator is released from phospholipid metabolism by PLA2?
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Platelet Activating Factor (PAF)
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What is the rapidly developing systemic allergic reaction that can lead to shock and even death?
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Systemic Anaphylaxis
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What are common causes of systemic anaphylaxis?
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Foods, drugs, insect venom
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What are 2 clinical settings in which anaphylaxis could occur?
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-Allergy shots
-Anesthesia |
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Who discovered anaphylaxis and how?
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Richet and Portier by studying portugese man of war in dogs.
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What are the 2 main clinical manifestations of anaphylaxis?
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1. Hypotension via vasodilation
2. Airway obstruction via laryngeal edema |
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What is used to treat anaphylaxis?
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Epinephrine
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What is Type II hsn mediated by?
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Antibodies against normal or altered cell surface antigens.
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What are the 3 mechanisms by which antibody causes Type II hsn?
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1. C' activation / opsonization
2. ADCC - KILLS the cell 3. Ab mediated cell DYSFUNCTION |
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What is a Type II HSN disease in which Ab mediates cell dysfunction by STIMULATING it?
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Graves disease
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What is the antibody directed against in grave's disease?
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The TSH receptor on thyroid epithelial cells
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What is a Type II HSN disease in which Ab mediates cell dysfunction by INHIBITING it?
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Myasthenia gravis
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What is the antibody directed against in Myasthenia gravis?
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The ACh receptor
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So what is impaired in Myasthenia gravis?
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Neuromuscular transmission
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List 8 examples of Type II HSN disorders:
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1. Grave's disease
2. Myasthenia gravis 3. Goodpasture's 4. Bullous pemphigoid 5. Pernicious anemia 6. Vasculitides 7. Thrombotic phenomena 8. Acute rheumatic fever |
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What is the Ab specificity in Goodpastures?
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Type 4 collagen
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What are the clinical features of goodpastures?
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-Nephritis
-Lung hemorrhage |
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What is the Ab specificity in Bullous pemphigoid?
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Epidermal basement membrane proteins
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What are the clinical features of Bullous pemphigoid?
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Skin vesicles
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What is the Ab specificity in Pernicious anemia?
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Intrinsic factor (from parietal cells in the gut)
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What are the clinical features of pernicious anemia?
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Megaloblastic anemia
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What is the Ab specificity in Vasculitides?
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Neutrophil cytoplasmic antibodies
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What is the Ab specificity in Thrombotic phenomena?
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Antiphospholipid antibodies
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What is the Ab specificity in Acute rheumatic fever?
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Streptococcal antibody that crossreacts with the heart
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What is the clinical feature of acute rheumatic fever?
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Carditis
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What is a predominant site of autoantibody deposition in Goodpasture's syndrome?
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The glomerulus
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