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138 Cards in this Set
- Front
- Back
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What are the 3 things that immunology involves?
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1. Distinguish self from non-self
2. Mechanisms of defense 3. Regulation and return to normal |
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What is the goal of the immunological system?
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Maintain homeostasis
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What are the 2 types of threats/insults you can have?
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1. internal
2. external |
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What are the 3 external threats/insults?
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1. Microorganisms
2. Parasites 3. Mechanical/chemical |
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What are the 3 internal threats/insults?
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1. Cancerous cells
2. Abnormal cells 3. Old/damaged cells |
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What are 3 types of inappropriate reactions that the body has to threats/insults?
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1. allergies
2. autoimmunity 3. transplant |
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What are the 3 lines of defense?
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1. exterior barrier
2. innate immune response 3. adaptive immune response |
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How is reinfection prevented?
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combined effort of innate + adaptive immunity
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What are the 4 types of mechanical/physical barriers?
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1. skin
2. mucus 3. cilia lining mucosa 4. mechanical (coughing, sneezing) |
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What are the 3 types of chemical barriers?
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1. sweat - prevent microbial growth on skin
2. lysozyme (tears, saliva, nasal secretions) 3. acidic environment (urine/vaginal secretion & stomach HCl |
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What are the 3 external defense mechanisms?
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1. mechanical/physical barrier
2. chemical barrier 3. bacterial interference |
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What is the goal of innate immunity?
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1. Control/eliminate threat
2. prepare for appropriate adaptive response |
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When is innate immunity present?
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Before threat
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Does innate immunity require pre-activation?
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No - does NOT
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What type of response is innate immunity (speed)?
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Rapid response
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How is innate immunity activated?
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By damage
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What does innate immunity determine?
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Type of adaptive response
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How is adaptive immunity the same as innate immunity?
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Present before threat
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How is adaptive immunity different from innate immunity (speed)?
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Adaptive takes days to weeks for full effect; innate is rapid
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In what circumstances is adaptive immunity activated?
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If threat is high enough for long enough time
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What are other attributes of adaptive immunity?
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1. specific for given antigen
2. establishes memory |
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What are the goals of adaptive immunity?
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1. eliminate threat
2. establish long-term memory |
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What are the different types of cells involved in innate immunity?
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1. monocytes/macrophages
2. NK cells 3. mast cells 4. granulocytes 5. complement 6. acute phase response 7. some cytokines |
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What are the types of granulocytes?
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1. neutrophils
2. eosinophils 3. basophils |
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What are the 2 types of adaptive immunity?
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1. humoral immunity
2. cellular immunity |
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What type of immunity do antibodies fall under? From what cells are they derived?
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Humoral immunity; B cells
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What type of immunity involves cytokines and direct killing? What cells are involved in this type of immunity?
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Cellular immunity; T cells
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What are the 2 types of stem cells that stem cells divide into?
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1. lymphoid stem cell
2. myeloid progenitor |
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What are the 3 types of lymphocytes?
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1. B cell progenitor
2. T cell progenitor 3. natural killer cells |
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What are the 2 types of B cell progenitor?
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1. Plasma cells
2. memory cells |
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What are the 2 types of T progenitor cells?
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1. Th cells
2. Tc cells |
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What are the 5 types of granulocytes?
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1. neutrophils
2. eosinophils 3. basophils 4. mast cells 5. monocytes |
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What are the 2 types of monocytes?
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1. dendritic cells
2. macrophages |
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Describe lymphocytes. What percent of WBC do lymphocytes consist of?
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Small w/ virtually no cytoplasm
10-40% |
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What are the 2 types of T cells?
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1. CD4+ cells (helper)
2. CD8+ cells (cytokines) |
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What do CD4+ cells do?
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Make/secrete cytokines to modulate immune system
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What do CD8+ cells do?
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Kill infected cells
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What do B cells do?
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Secrete antibodies
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What do NK cells do?
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Activated by Ab to kill
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Describe granulocytes. What percent of WBC do granulocytes consist of?
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multilobed nuclei & intracytoplasmic granules
40-70% |
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What are neutrophils? What percent of granulocytes do they make up?
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Short lived phagocytic cells
40-70% |
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What are eosinophils? What percent of granulocytes do they make up?
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Active against parasites & associated w/ asthma/allergies
1-3% |
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What are basophils? What percent of granulocytes do they make up?
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involved in histamine reaction
<1% |
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What are monocytes/macrophages? What percent do they make up?
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engulf microorganisms or debri and kill them; process & present foreign antigens to lymphocytes
5-10% |
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What are dendritic cells? Where are they found?
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Present foreign antigens to lymphocytes
- in tissues |
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What are mast cells? Where are they found?
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Active against bacteria & parasites; associated w/ allergy
- in tissues |
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What are the 3 pathways of complement activation?
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1. classical pathway
2. lectin pathway 3. alternate pathway |
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What is the classical pathway?
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Antibody binds to specific antigen on pathogen surface
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What is the lectin pathway?
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Mannose-binding protein binds to pathogen surface
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What is the alternate pathway?
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Pathogen surface creates local environment conducive to complement activation
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What 3 things does complement activation result in?
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1. Recruitment of inflammatory cells
2. Opsonization of pathogens, facilitating uptake & killing by phagocytic cells 3. Lysis and death of pathogens |
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What is the major difference b/w innate and adaptive immune response?
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Innate is non-specific whereas as adaptive is specific
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What is the ultimate goal of complement pathways?
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Create MAC (membrane attack complex)
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What do MACs do?
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Make holes in pathogen cell membranes and destroy pathogen
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In the classical pathway:
What does C1 split and what is does it form? |
splits C4 and results in C4a and C4b
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In the classical pathway:
What does C4b split and what does it form? |
splits C2 and results in C2a and C2b
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In the classical pathway:
What complex do the C4's and C2's form? |
C4bC2b
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In the classical pathway:
What does C4bC2b split and what does it form? |
splits C3 and results in C3a and C3b
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In all pathways:
What does C3b split and what does it form? |
splits C5 and forms C5a and C5b
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In all pathways:
What does C5b do? |
Finds C6, 7, 8, 9 and forms MAC
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In the lectin pathway:
What is the starting material? What step of the classical pathway does the lectin pathway enter at? |
Mannan -> C4bC2b
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In the alternate pathway:
How does the pathway start? |
Spontaneous splitting of C3
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In the alternate pathway:
What does C3 split into? |
C3a and C3b
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In the alternate pathway:
What does C3b do? |
Splits factor B into Ba and Bb
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In the alternate pathway:
What complex do the products of the C3 and Factor B split form? |
C3bBb
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In the alternate pathway:
What does C3bBb split? |
Splits C3 into C3a and C3b
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What part of the classical pathway does the alternate pathway enter at?
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C3 split into C3a and C3b
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What are the 3 ways that C3 splits, and in what pathways?
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1. Spontaneous in alternate
2. C3Bb in alternate 3. C4bC2b in both classical and lectin |
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Which complement is the most important in forming MAC?
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C5b (the ultimate goal to make MAC)
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How can the 1/2 life of complement be described?
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Short
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What does C1-INH do, and how?
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Inhibits C1 by cleaving it
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What inhibits soluble C3b
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Factor H
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What inhibits membrane bound C3b and how?
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Factor I, by converting it to iC3b
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What are the two factors that inhibit C3b, and form does each particular one inhibit?
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1. Factor H (soluble C3b)
2. Factor I (membrane bound C3b) |
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What inhibits C4bC2b?
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Decay accelerating factor
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What is C3b?
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Opsonin, clear immune complexes
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What are the 3 complements (in degree of strength) that are responsible for anaphylatoxin, activating vascular endothelium, chemoattractant, and activating phagocytes?
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C5a > C3a >> C4a
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What are C5a, C3a and C4a responsible for? What is the order of their strength?
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Anaphylatoxin
Activating vascular endothelium Chemoattractant Actavating phagocytes C5a > C3a >> C4a |
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What do C5b - C9 do?
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Cellular damage and lysis
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What is positive selection?
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Removal of lymphocytes that cannot bind HLA
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What is negative selection?
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Removal of lymphocytes that bind HLA too strongly
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How is binding increased during double selection?
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1. Double positive
2. Increase proteins to stabilize binding |
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What are the steps of T-cell education?
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1. Stem cells
2. Pre-T cells 3. Double Negative T-cells 4. Double Positive T-cells 5. a. bind neither --> death b. bind class 1 --> CD8+ T cell c. bind class 2 --> CD4+ T cell 6. CD8+ & CD4+ --> a. bind strongly --> die b. bind weakly --> live |
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What are the 3 possibilities double positive T cells and what are their fates?
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1. bind neither class - die
2. bind class 1 - CD8+ 3. bind class 2 - CD4+ |
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Of the 3 possible paths of double positive T cells, which is positive selection?
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Binding neither class I/II and subsequent death
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What are the 2 fates of CD4+ and CD8+?
Which is negative selection? |
1. bind strongly and die
2. bind weakly and live Bind strongly and die |
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What are the 2 signals for pre-CTL (cytotoxin T-lymphocyte) to become CTL
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1st signal: HLA class I (any cell) + TCR (CD8+ T cell)
2nd signal: IL-2 (from CD4+ T cell or DC) |
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What are the 2 signals for CD4+ T cells that cause it to secrete IL-2 (T-cells) & IL-4 (B cells)?
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1st signal: HLA class II (B, DC, Mϕ) + TCR (CD4+ T cell)
2nd signal: IL-1 (from B, DC, Mϕ) |
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Where are the only places that MHC class II (CD4+) cells found?
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BDM (b-cell, dendritic cells and macrophages)
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On what cells can MHC class I (CD8+) cells be found?
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All cells except red blood cells
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How many signals are required by naive T-cells to induce immunity?
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1st and 2nd signal
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How many signals do effector/memory cells require to induce activity?
What is/are that/those singal/s? |
1st signal
binding of HLA-Ag |
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What are the 2 activities of CD4+ T cells?
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1. Antigen:receptor binding and co-stimulation of T cells by DC
2. Antigen:receptor binding and activation of B cells by T cells |
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What 2 signals to B cells require to live?
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1st signal: Ab binding to Ag
2nd signal: IL-4 from CD4+ T cells |
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What is the purpose of 2 signals for B cells?
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Prevents autoreactive B cells since they don't undergo education like T cells
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What do naive B cells express?
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IgD and IgM
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What do CD4+ T cells activate?
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Isotype switching
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What does activation of B cells allow for?
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Change of effector characteristics
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What are other isotypes besides IgD and IgM
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IgG, IgE, IgA
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How are isotypes determined?
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Fc region
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How does antibody hypervariability occur?
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Inherited gene segments form unique combinations through somatic gene arrangement and chains pair to give a unique receptor for each lymphocyte
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What is the major effector function of IgM?
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Activation of complement system
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What is the major effector function of IgG1?
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Opsonization
Transport across placenta Diffusion into extravascular sites |
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What is the major effector function of IgG2?
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Diffusion into extravascular sites
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What is the major effector function of IgG3?
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Activation of complement system
Diffusion into extravascular sites |
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What is the major effector function of IgG4?
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Diffusion into extravascular sites
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What is the major effector function of IgA?
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Transport across epithelium
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What is the major effector function of IgE?
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Sensitization of mast cells
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How do specific antibodies act on bacterial cells that attach to receptors on cells for the toxin?
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Neutralize the toxin and ingested by macrophages
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How do specific antibodies act on bacteria in extracellular space?
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Opsonization and ingestion by macrophages
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How do specific antibodies act on bacteria in the plasma?
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Complement activation and lysis and ingestion
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What are examples of antibody mediated activities?
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1. Generation of oxidants
2. immunomodulation 3. opsonization 4. activation of complement 5. virus and toxin neutralization 6. antibody-dependent cell cytotoxicity 7. antimicrobial activity 8. reduced damage to host cell from inflammatory response |
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Characteristics about IgM?
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1. most effective immune response against LPS in gram - bact.
2. Very high complement activation |
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Characteristics of IgG?
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1. neutralizing Abs (viruses, toxins)
2. binding to IgG receptors mediates phagocytosis of antigen and activation of immune response 3. activation of complement 4. activation of natural killer cells (ADCC) |
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Characteristics of IgA?
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1. mediates direct killing of bacteria and tumor cells
2. secretory IgA protects against microbes on mucosal surfaces (gut, resp. tract, etc) |
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Characteristics of IgE?
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1. binding to IgE receptors can mediate allergic response
2. effective against parasites |
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Which isotypes are monomers?
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IgD, IgE, IgG
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Which isotypes are dimers?
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IgA
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Which isotypes are pentamers?
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IgM
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What are the steps of B cells activation and memory?
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1. B cell encounters & binds to antigen
2. B cell c responds to antigen by proliferating 3. Some B cells differentiate into long-lived memory cells 4. Other B cells differentiate into plasma cells 5. Plasma cells secrete Abs into circulation |
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What is the normal and deficient response to an infectious agent?
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Protective immunity
recurrent infection |
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What is the normal and deficient response to an innocuous substance?
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allergy
no response |
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What is the normal and deficient response to a grafted organ?
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rejection (nL response)
acceptance (deficient response) |
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What is the normal and deficient response to self organ?
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autoimmunity (nL response)
self tolerance (deficient response) |
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What is the normal and deficient response to a tumor?
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tumor immunity
cancer |
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How do lymphocytes and lymph return to blood?
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Via thoracic duct
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From where do naive lymphocytes enter lymph nodes?
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From blood
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How do antigens from sites of infection reach lymph nodes?
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Via lymphatics
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What are the 2 types of immunity?
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1. innate (genetic)
2. acquired |
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What are the 2 types of acquired immunity?
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1. active (own Abs)
2. passive (ready-made Abs) |
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What are the 2 types of active immunity?
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1. Natural - exposure to infectious agents
2. artificial - immunization |
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What are the 2 types of passive immunity?
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1. Natural - maternal Abs
2. Artificial - Abs from other sources |
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Type I: IgE
1. antigen 2. effector mechanism 3. ex. of hypersensitivity rxn |
1. soluble
2. mast-cell activation 3. allergic rhinitis, asthma, systemic anaphylaxis |
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Type II: IgG
1. antigen 2. effector mechanism 3. ex. of hypersensitivity rxn |
1. cell- or matrix- associated antigen
2. complement, FcR+ cells (phagocytosis, NK cells) 3. some drug allergies (PCN) |
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Type II: IgG (other)
1. antigen 2. effector mechanism 3. ex. of hypersensitivity rxn |
1. cell-surface receptor
2. Ab alters signaling 3. chronic urticaria |
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Type III: Th1 cells
1. antigen 2. effector mechanism 3. ex. of hypersensitivity rxn |
1. soluble
2. macrophage activation 3. contact dermatitis, tuberculin rxn |
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Type III: Th2 cells
1. antigen 2. effector mechanism 3. ex. of hypersensitivity rxn |
1. soluble
2. eosinophil activation 3. chronic asthma, chronic allergic rhinitis |
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Type III: CTL
1. antigen 2. effector mechanism 3. ex. of hypersensitivity rxn |
1. cell-associated antigen
2. cytotoxicity 3. contact dermatitis |
