HIV

• HIV structure:

  • membrane envelope - outer layer
  • capsid - protects genetic information
  • RNA (can be DNA in others)
  • glycoprotein - the antigens
  • reverse transcriptase enzyme - turns RNA into DNA
• HIV works by invading T cells, which prevents humoral response. The virus replicates in the T cells until they swell and burst. Over time the number of T cells decreases and eventually causes AIDs
• How HIV replicates:

  • glycoproteins molecules on the virus surface bind to CD4 receptors on the surface of T helper cells. envelope surrounding the virus with the T helper cell membrane
  • the capsid is released into the cell where it releases RNA and reverse transcriptase
  • reverse transcriptase us used to make DNA from the HIV RNA
  • the DNA is inserted into the cells DNA which gets replicated when cells replicate
  • DNA used to make HIV RNA and proteins at host ribosomes
  • virus particles are assembled and bud off from the cell and go to infect other cells
• AIDS is contracted when the T-helper cells reach a critically low level
• HIV can remain dormant in host cells and it can take around ten years for a HIV patient to develop AIDS
• Antiretroviral drugs are now available which can reduce the viral load in the body to an undetectable level
• antiretroviral drugs slow the replication of the virus by blocking the reverse transcriptase enzyme