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24 Cards in this Set
- Front
- Back
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Description of retroviruses structure
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enveloped RNA, RT
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HTLV-1,-2
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human t-cell leukemia virus
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Classification of HIV
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lentiviruses (HIV-1 and HIV-2)
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4 groups of HIV, which is most common?
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M, O, N and P (main is M)
Type M is further divided to circulating recombinant forms |
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Structure of HIV
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Has envelope (needs warm and moist enviro)
Has critical proteins (GP120-[binds CD4] and GP41-[fusion] 2 RNA strands Has RT and integrase (both in viral particle) Protease tags along. |
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HIV-1 life cycle (entry)
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gp120 binds to CD4 on T cells as primary receptor
CCR5 or CXCR4 are co-receptors |
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Most viruses that initially infect people use what secondary receptor?
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CCR5
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Reverse transcription core tenants
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lots of errors, which leads to multiple presentations and difficult to treat
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What does the virus have to do in order to replicate?
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Integration of HIV DNA into nucleus
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What protein plays a role in inserting the HIV into the DNA strand?
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integrase
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What is an irreversible step in the HIV replication process?
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Strand transfer (not yet known how to identify)
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What happens during the maturation step?
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HIV protease places the capsid onto the virus itself
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Main target cell population of HIV-1?
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uninfected, activated CD4 lymphocytes
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What is one of the main tx problems with HIV?
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Latency in CD4+
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HIV transmission
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Sex
Maternal-fetal (peripartum, breast feeding) Parenteral (injection, needle sticks, clotting) |
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Greatest risk of HIV infection routes
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Transmission from mother to infant, needle sticks
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Two divisions of HIV pathogenesis
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Acute (events prior to and during initial host response)
Chronic (interplay between viral replication, immune activation, and host response) |
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Acute infection of HIV
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Presentation from CD4+/DC to lymph nodes, proliferates in lymph nodes and then into blood
(total time about 14 days) |
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Where is the highest concentration of CD4+/CCR5+ cells?
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Gut (huge depletion of T cells in gut during Acute HIV)
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Describe the viremia #, area of desctruction, and initial antibody response to acute HIV.
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HIV RNA can be >1,000,000 in individuals, most destruction of T cells in GI tract, weak and ineffective antibody response bc T cells programmed to HIV are the ones hijacked
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Host responses to HIV
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Innate responses (NK cells)
HIV-1 Ab Cellular Immune responses Neutralizing Ab |
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Overview of HIV pathogenesis
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During acute (8-12 weeks), huge replication of virus and depletion of CD4+.
CD8+ controls HIV infection (w/o CD8+, possibly die) Initial Ab only used to identify Neutralizing Ab generally only work for virus in past. |
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Which affect disease progression more: viral or host?
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Host
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Host factors affecting disease progression (CD4+ loss)
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co-receptor genotypes
MHC genotypes Breadth and strength of immune response Production of beta-chemokines (CCR5 ligands) |
