Questions and Answers
What glycoprotein on the HIV virus is essential for binding to CD4+ cells?
Which HIV strain is the most prevalent in Africa?
During which stage of the HIV infection cycle does reverse transcription occur?
What role does the chemokine receptor CCR5 play in HIV infection?
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Which of the following is NOT a way that HIV can be transmitted?
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What occurs during the 'Assembly' stage of the HIV life cycle?
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Which enzyme is released by HIV to break down long chains of proteins in immature viruses?
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What is the primary target cell for HIV in the human immune system?
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Which stage of the HIV life cycle involves the integration of HIV's viral DNA into the host cell's DNA?
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What happens during the 'Replication' stage of HIV's life cycle?
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Study Notes
HIV Strains
- HIV-1 is the most prevalent strain in the United States.
- HIV-2 is primarily found in Africa.
Transmission Routes
- HIV is transmitted through direct contact with infected blood and body fluids, including:
- Breastmilk
- Rectal and vaginal secretions
- Preejaculate/semen
- Infection occurs via mucous membranes located in the rectum, vagina, penis, or mouth.
- Common modes of transmission:
- Injection drug use
- Maternal-child transmission during childbirth or breastfeeding
- Blood transfusions (less common)
Target Cells and Entry Mechanism
- HIV targets specific cells:
- Macrophages
- Dendritic cells
- CD4+ helper T cells
- The outer surface of HIV contains glycoprotein 120 (GP-120):
- Binds to CD4+ receptors on dendritic cells.
- GP-120 also binds to chemokine receptors for viral entry:
- CCR5 for macrophages
- CXCR4 for T cells
HIV Life Cycle
- Binding/Attachment: HIV attaches to CD4 cell receptors.
- Fusion: HIV envelope fuses with the CD4 cell membrane, allowing entry.
- Reverse Transcription: HIV utilizes reverse transcriptase to convert HIV-RNA into HIV-DNA inside the CD4 cell.
- Integration: HIV releases integrase to insert viral DNA into the CD4 cell’s DNA.
- Replication: Integrated HIV DNA directs production of long chains of HIV proteins using the cell’s machinery.
- Assembly: New HIV proteins and RNA gather at the cell surface and form immature (noninfectious) HIV particles.
- Budding: Immature HIV exits the CD4 cell, where protease enzymes break down long protein chains to produce mature, infectious HIV.
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Description
Test your knowledge on the two primary strains of HIV, their prevalence in different regions, and how the virus is transmitted. This quiz covers key facts about HIV transmission routes, including bodily fluids and potential infection scenarios.
