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6 Cards in this Set
- Front
- Back
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What are the three types of immunity against viruses? Give examples. |
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How does the immune system combat viruses? |
•Infection is prevented by type I interferons as part of innate immunity and neutralizing antibodies contributing to adaptive immunity. •Once infection is established, infected cells are eliminated by NK cells in the innate response and cytotoxic T cells in the adaptive response. - main weapons are type 1interferons (preventing infections due t antiviral state) and NK cells (killing infected cells) |
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Describe how antibodies combat viruses (4) |
- bind and inactivate virions •Bind to capsids or envelope proteins and neutralise i.e. block receptor or change receptor conformation •opsonisation of virus particles – phagocytic clearance •phagocytosis and lysis of enveloped viruses through activation of complement |
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How do cytotoxic T-lymphocytes combat viruses? (4) |
•CTLs kill virus-infected cells •T cells are activated by engaging with MHC-viral peptide complex •Perforin and granzyme molecules destroy the infected cells •CD8+ T cells produce cytokines and chemokines that recruit antiviral T cells and clear viral infection |
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List 4 viral evasion strategies |
• Disarm innate immunity • prevent MHC presentation • hide e.g. in non-differentiated cells (e.g. herrpes simplex) • modification of viral ligands to prevent recognition |
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List 3 consequences of viral divergence |
- increased infection e.g. pandemics - change in host e.g. species - resistance to antivirals and vaccines |
