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36 Cards in this Set
- Front
- Back
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what is the structure of influenza
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-RNA strand
nuclear envelope with glycoproteins: HA- hemaglutinin NA - neuraminidase |
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explain antigenic shift and antigenic drift.
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influenza
no proofreading --> error prone genome --> slow antigenic drift RNA is segments --> reassortment of sgments --> sudden antigenic shift |
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Describe each step of the viral replication cycle
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1. HA binds scialic acid ---> endosome
2. HA fuses w/ memb M2 ion channels acidify endos ---> virus disassembles 3. -RNA enters nucleus--transc repli NS1 with three functions: 1.) binds mRNA polyA tail 2.) blocks PKR 3.) mediates nuclear export of -RNA copies 4.) NA cleaves scialic acid, releasing HA anchor |
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What is different about influenza from other RNA viruses?
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RNA goes into nucleus
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Does swine flu come from pigs? Why did cause such a commotion?
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No - is a reassortment of 1 human strain, 1 bird strain, and 2 pig strains of influenza A
Concern - ability to pick up genomic components very easily (antigenic shift - reassortment) - vaccines difficult to treat |
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What are the different kinds of antiviral drugs against influenza?
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1. amantadine and rimantidine
prevent uncoating of virus by inhibit M2 channel protein 2. zanamivir and oseltamivir NA inhibitor --> prevents exit of virus 3. vaccines mixtures of HA and NA subtypes from diff strains |
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where does influenza like to colonize. what is NA's role in colonization
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upper respiratory tract
NA cleaves scialic acid of mucus - clearing path to epithelial cells |
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Flu symptoms are actually due to
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interferon and T-cell response
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Influenza promotes bacterial adhesion to epith cells. What secondary infections are possible?
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Streptococcus pneumoniae
Haemophilus influenzae Staphyloccus aureous |
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What is structure of HIV?
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glycoproteinated envelope
truncated cone core with 2 copies of +RNA has reverse transcriptase and 2 tRNAs |
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What gene encodes the glycoproteins? How are they individually made?
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env gene encodes a polyprotein
polyprotein gp160 is cleaved to generate glycoproteins: gp120 - binds receptors, dter cell tropism - undergoes antigenic drift to avoid immune detection gp41 - cell-cell fusion |
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how does HIV dock onto cell?
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1. CD4 binding via gp120 trimer
2. coreceptor binding to gp120 (CCR5/CXCR4) 3. trimer spike opens --> virus-cell fusion via gp41 |
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WHat does gag encode?
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virion core proteins:
capsid matrix nucleic acid binding protein NC? |
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what do pol genes encode?
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enzymes:
reverse transcriptase (polymerase) protease - for maturation integrase - help to integrate into host genome |
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name 3 accessory gene products
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tat - transactivator - controls transcription of viral genes
rev - regulator virion protein promotes viral RNA exit from nucleus nef - negative regulatory factor - required for viral titer vif - virion infectivity factor - promotes assembly and maturation vpu - viral protein U - required for budding vpr - transcrtional activator - promotes virus replication in nongrowing cells such as macrophages |
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What are LTRs?
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long terminal repeat sequences viral genome
contain promoters and enhancers to promote transcrtiption act as sites for integrase to act on |
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how are accesssory genes produced???
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alternative splicing of mRNA????
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Describe structure and function of integrase
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3 domains - SH3, n-terminal zinc finger for multimerization, catalytic domain
2 functions - create sticky ends (3' end processing - remove 3 nts), and ligation |
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what is the hallmark feature of AIDS
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HIV induced immunosuppression
reduce CD4 helper T cells and CD8 T cells |
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Describe the pathogenic course for AIDS
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1. initial spike in virus titers (mono like symptoms) elicits an immune response (inc in T cell count dec in virus)
2. latency period - with gradual dec in Tcell count 3. AIDS occurs in late stages when immune depleted |
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name 3 accessory gene products
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tat - transactivator - controls transcription of viral genes
rev - regulator virion protein promotes viral RNA exit from nucleus nef - negative regulatory factor - required for viral titer vif - virion infectivity factor - promotes assembly and maturation vpu - viral protein U - required for budding vpr - transcrtional activator - promotes virus replication in nongrowing cells such as macrophages |
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WHat are the classic list of symptoms for AIDS
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ARC - AIDS related complex:
lymphadenopathy diarrhea, nightsweats fever, wasting disease fatigue |
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Name some opportunistic infections of AIDS
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poxvirus, herpesvirus, DNA virus, bacteria, EBV (epstein barr virus), TB etc
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What are LTRs?
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long terminal repeat sequences viral genome
contain promoters and enhancers to promote transcrtiption act as sites for integrase to act on |
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What are the primary malignancies in AIDS patients
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Kaposi's sarcoma virus
EBV related lympomas |
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how are accesssory genes produced???
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alternative splicing of mRNA????
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What are dementias related to AIDS
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slow deterioration of intellectual abilities - alzheimer like symptoms
cuased by infectino of macrophages and microglia in brain (macrophages of the brain) |
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Describe structure and function of integrase
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3 domains - SH3, n-terminal zinc finger for multimerization, catalytic domain
2 functions - create sticky ends (3' end processing - remove 3 nts), and ligation |
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what is the hallmark feature of AIDS
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HIV induced immunosuppression
reduce CD4 helper T cells and CD8 T cells |
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Describe the pathogenic course for AIDS
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1. initial spike in virus titers (mono like symptoms) elicits an immune response (inc in T cell count dec in virus)
2. latency period - with gradual dec in Tcell count 3. AIDS occurs in late stages when immune depleted |
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WHat are the classic list of symptoms for AIDS
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ARC - AIDS related complex:
lymphadenopathy diarrhea, nightsweats fever, wasting disease fatigue |
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Name some opportunistic infections of AIDS
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poxvirus, herpesvirus, DNA virus, bacteria, EBV (epstein barr virus), TB etc
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What are the primary malignancies in AIDS patients
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Kaposi's sarcoma virus
EBV related lympomas |
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What are dementias related to AIDS
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slow deterioration of intellectual abilities - alzheimer like symptoms
cuased by infectino of macrophages and microglia in brain (macrophages of the brain) |
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What are the top 5 antiretroviral drugs on the market?
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1. (NRTI) nulceoside reverse transcriptase inhibitor - binds to active site - ie azidothymadine (AZT)
2. non-nucleoside RTI (NNRTI) - allosteric bindnig - ie nevirapine 3. PI - protease inhbitior 4. CCR5 inhibitor (fusion inhibitor) 5. integrase inhibotr - ie Raltegravir |
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What is HAART?
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= higly active antiretroviral therpy
it is a cocktail of antiretroviral drugs NNRTI + 2 NRTI or 2PI + 2NRTI |
