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23 Cards in this Set
- Front
- Back
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List three general PAMPS
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1. ssRNA or miRNA in the cell endosome
2. dsRNA in the cell endosome or cytoplasm 3. Unmethylated CpG DNA |
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WHich TLRs haven been shown to be important in the context of viral infection
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2, 3, 7,8, 9
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Which cells express TLR3 and what does it recognize
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expressed by all cells, recognizes dsRNA on the cell surface and in the endosome
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Which TLR exacerbates herpes simplex virus encephalitis
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TLR2
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What is unique about TLR 7 and 8 expression
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differentially expressed, only highly expressed in immune cells (dendritic cells or monocytes)
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Which TLR recognizes rotavirus
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TLR3
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Which TLR recognizes ssRNA viruses
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TLR7
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Which TLR recognizes Herpes viruses siRNA
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TLR8
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Which TLR recognizes DNA viruses like herpes and pox
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TLR9
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Why do RNA viruses replicated in membrante compartments
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To avoid immune detection by RIG-1 and PKR
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Explain the purpose of RIG-1 in innate defense against viral pathogens
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Binds cytoplasmic RNA and initiates a signal transduction cascade that upregulates NFkb and interferon
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List the 4 ways the viruses can activated NFkb
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1.viral protein overproduction
2. RNA helicases like Rig 1 and PKR 3. Signal transduction upon virus particle binding to its receptor 4 viral proteins directly engage signal transduction pathways |
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Explain how viral protein overproduction leads to NFkb activation
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virus protein overproduction leads to ER overload and increase Ca2+. The Ca turns off the Ikb's thus allowing NFkb to become active
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What are defensins?
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Proteins released by neutrophils that have anti-viral properties (detergent propety is good against viral envelope)
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Which MHC is responsible for presenting self peptides
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MHC class 1
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When viruses infect cells, they decrease MHC class 1 expression on the cell surface. What is the consequence of this?
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If MHC class I is not being expressed, NK cells do not receive a - kill signal. The infected cell is killed with NK cell perforin and granzyme (protease that activates caspases)
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How does human cytomegalovirus avoid the NK cell mediated killing in response to MHC I down regulation?
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HCMV produces an MHC homolog called UL18 which presents peptides. The homolog binds inhibitory NK receptors (LIR-I) with 1000 fold higher affinity than host MHC this fakes the "don't kill" signal that would normally be given by celluarl MHC 1 presentation
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How do herpes viruses interfer with antigen presentation?
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Some herpes viruses can encode a protein called mk3 which is a ubiquitin ligase. This protein targets the host MHC I complex for degradation this decrease the amount of viral antigen being presented
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What are the professional antigen presenting cells
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macrophage, dendritic cell, b cell
express MHC II |
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Describe the innate immune function of Dendritic cell.
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-APC
-Tissue resident (skin= langerhans cells) -interact w/ T and B cells in lymph node |
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Compare and Contrast MHC I and II in terms of origin of the peptides they present
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MHC I= internal
MHC II= external |
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Compare and Contrast MHC I and II in terms of which cells have them
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MHC I = all nucleated cells
MHC II= APCs only |
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Compare and Contrast MHC I and II in terms of structure
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MHC 1= 4 domains
MHC II = 2 domains |
